# Difference between 2D & 3D Drawings

## TWO-DIMENSIONAL (2D) DRAWINGS

The abbreviation for two-dimensional drawing is 2-D, and it describes a view having only width and height, width and length, or height and length dimensions. Two-dimensional drawings are the established design and drafting format and are common in all engineering and architectural industries and related disciplines.

The figure shows a drawing with two 2-D views representing the geometry of an aircraft part. The two views together provide width, height, and length dimensions. Views appear in ﬂat form and are normally rotated 90 degree from each other. A complete 2-D drawing typically includes dimensions, notes, and text that describes view features and details.

Two-dimensional drawings are the conventional and often required method of communicating a project. An effective 2-D drawing accurately describes design intent and product requirements, including the size, shape, and characteristics of all features, and materials, ﬁnishes, and manufacturing or construction methods. A 2-D drawing also typically documents additional project information, such as the individuals and companies involved with the project, relevant dates, approvals, and design revision history. Two-dimensional drawings can also provide computer numerical control (CNC) machine code. However, compared to 3-D surface and solid models, 2-D draw-ings offer fewer options for presenting and visualizing ideas and limited ability to analyze and test product design. In addition, 2-D drawings can sometimes be difﬁ cult to understand, especially if the reader is unfamiliar with interpreting 2-D drawings.

## THREE-DIMENSIONAL (3D) DRAWINGS

The abbreviation for three-dimensional is 3-D, and it describes an object having a width, height, and depth dimensions. A wire-frame model is the most basic 3-D CAD model, and it contains only information about object edges and vertices. The word vertices are plural for vertex, which is the point where edges intersect. The term wireframe describes the appearance of the model as if constructed from wires.

Three-dimensional surface and solid modeling have replaced wireframe modeling in the CAD industry. Wireframe models have limited use as models because they lack surfaces and mass. Without surfaces, wireframe models are difﬁcult to visualize, create uncertainty about design intent, do not provide a true representation of a product, and lack volume. Some software offers the ability to hide or change the format of the lines that fall behind object features to improve visualization and as a way to create a 3-D representation, or pictorial, view for a 2-D drawing. However, the display can still cause confusion, especially when viewing complex objects. Without volume or mass, wireframe models offer limited ability to analyze and test products.

A wireframe model does offer small ﬁle size and fast display regeneration because of the ﬁle only store edge and vertex data. Wireframe models can also serve as a basis for constructing 3-D surface and solid models, and they can provide the geometry for 2-D drawings. By rotating and repurposing a wireframe model, it is possible to produce the 2-D views shown in Figure. Wireframe models can also provide 3-D CNC machine code.

## THREE-DIMENSIONAL (3D) SURFACE MODELS

A surface model contains information about object edges, vertices, and surfaces (see Figure). A surface is an outer boundary of an object that connects to edges and vertices. Surfaces can display color, shading, reﬂection, and texture that signiﬁcantly improves visualization. Surfaces reduce uncertainty about design intent and provide a true representation of a product. Surface modeling also offers the ability to create complex curves and forms. The figure shows an example of a surface model with photorealistic surfaces and complex forms.

Three-dimensional surface modeling is common in the CAD industry, particularly for industrial and conceptual design and to construct certain shapes. A surface model has zero thickness, lacks mass, and may not enclose a volume. Surface models allow for basic calculations such as surface area and volume, but without mass, they offer limited ability to analyze and test physical and inertial properties. As a result, the most common users of surface models are designers who are primarily concerned with the external shape and appearance of a product. Boat and ship hull design is a common application for surface modeling. An automobile body panel is another example of a product that requires accurate surfaces. Animations, video games, virtual reality programs, and programs with similar requirements often use surface models because of the ability to form complex surfaces, especially when solids are unnecessary and ﬁle size is generally smaller than solid model ﬁles.

Surface models can serve as a basis for constructing 3-D solid models, and they can provide the geometry for 2-D drawings. By rotating and repurposing a surface model, it is possible to produce the 2-D views and display realistic surfaces on the 3-D representation, or pictorial, views. Surface models can also provide 3-D CNC machine code.

## THREE-DIMENSIONAL (3D) SOLID MODELS

3A solid model is the most complex CAD format, and it contains information about object edges, vertices, surfaces, and mass. An accurate solid model is an exact digital representation of a product. Like surface models, solid models can display surface color, shading, reﬂection, and texture for presentation and visualization. The figure shows an example of a photorealistic solid model. Solid models also offer the ability to create intricate curves and forms. However, some designs require surface modeling in order to produce the desired form for a solid model. Some solid modeling software includes surface modeling tools to help model complex shapes that only surface modeling can produce or create efﬁciently.

Solid models are the most common 3-D CAD format used in the current CAD industry. A solid model encloses a volume and has mass, which allows designers and engineers to analyze the exterior and interior object characteristics and perform interference and collision checks, mass calculations, and simulations. In contrast to a 2-D drawing that includes a note that speciﬁ es the material assigned to a product, and a 3-D surface model that displays a representation of material on surfaces, a 3-D solid model can be assigned a material that closely replicates the material used to manufacture the product. Assigning a material to a solid model allows for analyzing and testing physical and inertial properties. The result is a solid model that acts as a digital prototype of a product. Solid models can provide the geometry for 2-D drawings. By rotating and repurposing a solid model, it is possible to produce the 2-D views shown in Figure and display realistic surfaces on the 3-D representation or pictorial views. Solid models can also provide data for rapid prototyping and 3-D CNC machine code.

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# WHAT ARE THE DIFFERENT CADD FORMATS

There are several different CADD formats. The most recognized CADD formats include 2D drawings and 3D wireframe, surface, and solid models. In general, 2-D drawings and 3-D solid models are the most common CADD formats currently used in the industry. Three-dimensional surface models are also widely used, but often for speciﬁc applications. Three-dimensional wireframe models are rare in the current industry. Software speciﬁes the CADD format, which usually focuses on a certain process such as 2-D drawing or 3-D solid modeling.

However, some systems offer tools for working in a variety of formats or the ability to use drawing or model content created in a different format. For example, you can often develop a 2D drawing from 3D model geometry or build a 3-D solid model from 3-D surface model geometry. A software add-on or separate application is sometimes required to work with multiple CADD formats.

## CHOOSING A CADD FORMAT

Several factors inﬂuence CADD software and format selection. Design and drafting practices and speciﬁc project requirements are primary considerations. Two-dimensional drawings are often required because they are the standard format in manufacturing and construction.

The figure shows a 2-D structural detail required for the construction of a building. In addition, 2-D drawing is effective for a project that is quick to design, does not require extensive revision, and does not require advanced visualization, simulation, and analysis. Three-dimensional solid modeling is a better solution when a complex project will require extensive revision and when advanced visualization, simulation, and analysis are required. A 3-D representation of a design can help overcome visualization problems and produce a realistic, testable product model.

The figure shows a multidiscipline 3D model of a building providing structural, electrical, HVAC, and piping layouts. When applied correctly, a combination of CADD formats and software may prove most effective for a project. Bringing the advantages of each CADD format together maximizes product design ﬂexibility and effectiveness.

Collaboration and communication during a project also inﬂuence CADD software and format selection. Everyone involved in a project must be able to use a common CADD format or be able to easily convert data to a usable format. Costs are another important factor to consider when choosing a CADD software and format. For example, advanced 3-D solid modeling software is generally more expensive than 2-D drafting software. Operating a new or different CADD system also requires training and time to learn. Training is an expense and takes time from projects that produce income. A more capable CAD format, such as 3D solid modeling, is extremely cost-effective for some users, especially over time, but others will never beneﬁt from the initial costs of the software and training. Several additional factors also inﬂuence selecting CADD software and format, including choosing a product and a format that is a known industry standard for project requirements, software stability and usability, the availability and effectiveness of support and training, and personal preference.

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# INTRODUCTION TO COMPUTER-AIDED DESIGN AND DRAFTING (CADD)

## COMPUTER-AIDED DESIGN AND DRAFTING (CADD)

Computer-aided design and drafting (CADD) is the process of using a computer with CADD software for design and drafting applications. Software is the program or instructions that enable a computer to perform speciﬁc functions to accomplish a task. CADD refers to the entire range of design and drafting with the aid of a computer, from drawing basic 2-D objects to preparing complex 3-D models and animations. CAD is the acronym for computer-aided design and a common reference to computer-aided drafting. Computer-aided design and computer-aided drafting refer to speciﬁc aspects of the CADD process.

CADD offers solutions to most engineering drawing and design problems, and it allows for increasingly complex projects. Several industries and most disciplines related to engineering and architecture use CADD. Most engineering firms and educational institutions that previously used manual drafting practices have evolved to CADD. Professionals have come to rely on the power and convenience of CADD in all aspects of design and drafting. CADD systems include tools to accomplish any drawing and design requirement, such as preparing the 3-D model of a home shown in Figure.

## THE CADD WORKSTATION

The CADD workstation consists of a variety of computer hardware. Hardware includes the physical components of a computer system, such as the computer, monitor, keyboard, mouse, and printer. The figure shows a modern CADD work-station. A CADD workstation relies on a computer for data processing, calculations, and communication with peripheral equipment. A peripheral is an external computer hardware device that uses the computer to perform functions that the computer cannot handle.
Peripherals provide input, output, and storage functions and services. Input means to put information into the computer that the computer acts on in some way. Input comes from devices such as the keyboard, a mouse or similar input device, or a digitizer. Output refers to information that the computer sends to a receiving device such as a monitor, a plotter, or a printer. Storage refers to disks and drives that allow the operator to store programs, ﬁles, symbols, and data.

## CADD SOFTWARE PRODUCTS

The modern CADD workstation is powerful, inexpensive, and supports sophisticated CADD software. Many CADD software manufacturers exist, and numerous products are available to meet industry needs. Some CADD software is general purpose and can apply to any discipline. For example, Autodesk, Inc. produces AutoCAD for 2-D and 3-D design and drafting.

Other products focus on a speciﬁc CADD technology, industry, or discipline, such as drawings or models of mechanical parts and assemblies or those for architectural, civil, or structural engineering projects.

For example, Dassault Systèmes SolidWorks Corp. offers SolidWorks for 3-D solid modeling and 2-D drafting that is common in the manufacturing industry. Software speciﬁcally designed for CADD in the manufacturing industry is sometimes referred to as mechanical computer-aided design (MCAD) software. Some CADD programs support expanded, third-party, or add-on utilities intended to increase system usefulness for speciﬁ c applications.
The CADD software industry changes constantly. Software manufacturers frequently update existing products or combine, change program names, or eliminate programs to adapt to the rapidly evolving CADD market. Software updates typically include additional and reﬁned tools, increased software stability, and graphical user interface (GUI) enhancements.

The interface describes the items that allow you to input data to and receive outputs from a computer system. The GUI provides the on-screen features that allow you to interact with a software program. New products regularly emerge to respond to innovative technology and project requirements. Larger software manufacturers, such as Autodesk Inc., Dassault Systèmes, Parametric Technology Corporation, and Siemens PLM Solutions hold the greatest number of CADD users, and they traditionally have the ability to expand their products and acquire smaller software companies or existing software.

Some software manufacturers offer products intended to support various aspects of product development. For example, some software companies combine CADD and CAM tools for design, drafting, and manufacturing. A few software companies offer speciﬁc applications or software packages to help manage all aspects of a project, known as product life cycle management (PLM). PLM systems include tools for CADD, product data management (PDM) to organize and monitor project data, computer-aided engineering (CAE) for simulation and analysis, CAM, and presentation.

### Alibre, Inc.

Alibre provides software generally for CADD in the manufacturing industry. Alibre Design is a 3-D solid modeling and 2-D drafting program. The Professional version of Alibre Design includes tools for sheet metal design and rendering. The Expert version of Alibre Design provides additional functions such as simulation and FEA, PDM, CAM, and extended translation tools. Translation occurs when converting data from the ﬁ le system of one CADD system to another, and it is often necessary when sharing CADD data with others, such as consultants, manufacturers, and vendors. Most CADD soft-ware includes tools for some level of ﬁ le translation. Separate translation software is available when necessary. Alibre also offers Alibre Personal Edition, which is a 3-D modeling and 2-D drawing software marketed to hobbyists.

### Ashlar-Vellum

Ashlar-Vellum offers basic 2-D and 3-D CADD software. Graphite provides 2-D and 3-D wireframe drawing and modeling capabilities. Argon is a basic 3-D model-ing software for conceptual design, visualization, and translation. Xenon and Cobalt, which include additional functions, are 3-D modeling programs with 2-D drafting capabilities.

### Autodesk, Inc.

Autodesk offers a wide variety of soft-ware. AutoCAD is general-purpose 2-D and 3-D CADD software and is the core Autodesk product. Autodesk provides variations of AutoCAD for unique markets, such as Auto-CAD LT for 2-D drafting, AutoCAD Electrical for electrical control system design, and AutoCAD Civil 3-D for civil engineering project design. Additional Autodesk products focus on speciﬁ c CADD technology and industries, such as manufacturing, architecture, construction, infrastructure, media, and entertainment.
Autodesk® Inventor® is a 3-D solid modeling and 2-D drafting program generally for CADD in the manufacturing industry. Autodesk Inventor provides a comprehensive and ﬂexible set of software for 3-D mechanical design, simulation, design visualization and communication, tooling creation, and 2-D documentation. Autodesk offers Autodesk Inventor Suites that combine Autodesk Inventor, AutoCAD Mechanical, and tools for speciﬁ c applications, such as mold, tube and pipe, and cable and harness design. Some Autodesk Inventor Suites also include simulation and analysis functions. Autodesk Revit is a 3-D building design program with 2-D drafting and documentation capabilities. Versions of Autodesk Revit focus on design for architecture, mechanical, electrical, and plumbing (MEP), or building information modeling (BIM) for structural engineering. Autodesk manufactures numerous other software products, including Autodesk Algor Simulation for solid model simulation and FEA, Autodesk Vault for PDM, 3ds Max for 3-D modeling, animation, and rendering, and software to support the sustainable and environmentally friendly design and development.

### Bentley Systems, Inc.

Bentley Systems focuses on software for engineering and construction infrastructure design, documentation, and operation. Infrastructure is the structures, facilities, and services required for an economy to function, such as buildings, roads and bridges, water supply and sewer systems, and power-supply and telecommunication systems. Micro Station is a general-purpose 2-D and 3-D CADD soft-ware and is the primary Bentley Systems product. Micro-Station also acts as a platform for other Bentley Systems software. For example, GEOPACK Civil Engineering Suite includes tools for civil engineering and transportation project design. Micro Station PowerDraft is a version of MicroStation mainly for 2-D drafting. Bentley Systems manufactures other software, including Project Wise for PDM, and ProConcrete for 3-D modeling, detailing, and scheduling of reinforced concrete structures.

### Dassault Systèmes

Dassault Systèmes brands offer several soft-ware products generally focused on CAD and related technology for the manufacturing industry. CATIA is a project development system and is the main Dassault Systèmes brand product. CATIA provides tools for 3-D solid modeling and 2-D drafting and tools for speciﬁ c applications, such as mold, tube and pipe, cable and harness, and electronic design. CATIA also offers simulation and analysis, CAM, and PDM functions. The additional Dassault Systèmes brand software focuses on speciﬁ c aspects of PLM.
SolidWorks is a 3-D solid modeling and 2-D drafting program and is the core Dassault Systèmes SolidWorks (www. solidworks.com) brand product. Dassault Systèmes SolidWorks offers a standard version of SolidWorks and suites that incorporate SolidWorks with simulation, analysis, and PDM tools. SolidWorks Simulation includes tools for solid model simulation and FEA. SolidWorks Flow provides ﬂuid-ﬂow simulation and thermal analysis. Dassault Systèmes SolidWorks also manufactures software to support the sustainable and environmentally friendly design and manufacturing.

Google SketchUp is a software intended to have an easy to use interface for creating, sharing, and presenting 3-D models. Common applications for Google SketchUp include sketching and modeling for visualization during the conceptual design phase of a project and creating presentation drawings that look hand-sketched or photorealistic. Google SketchUp also links to Google Earth for sketching relative to a physical location, such as modeling a building on an actual lot.

### GRAPHISOFT

GRAPHISOFT focuses on software for the architecture, engineering, and construction (AEC) industry. ArchiCAD is a 3-D building design program with 2-D drafting and documentation capabilities; it is the main GRAPHISOFT product. MEP Modeler adds 3-D and 2-D MEP functions to ArchiCAD. Virtual Building is a 3-D digital database that tracks all elements that make up a building, allowing the designer to use items such as surface area and volume, thermal properties, room descriptions, costs, product information, and window, door, and ﬁnish schedules. Virtual refers to something that appears to have the properties of a real or actual object or experience. GRAPHISOFT also manufactures photo-realistic rendering software and software to support sustainable and environmentally friendly architectural design and construction.

### IMSI/Design, LLC

IMSI/Design offers basic CADD software for general-purpose and project-speciﬁc applications. TurboCAD is the core IMSI/Design product. IMSI/Design provides variations of TurboCAD for unique markets, such as TurboCAD Designer for 2-D drafting, TurboCAD Deluxe for 2-D drafting and 3-D modeling, and TurboCAD Pro with additional 2-D and 3-D CADD functions. Additional IMSI/Design products focus on speciﬁ c CADD technology and industries, such as Home & Landscape and Instant Architect for basic 2-D and 3-D home design.

### Intergraph

Intergraph manufactures software for speciﬁc industries and projects, including the design, construction, and operation of plants, ships, offshore facilities, and transportation and utility systems. For example, SmartMarine 3-D is specialized software for 3-D model-ing, design, and documentation of marine structures, such as commercial ships. Intergraph also offers SmartSketch for 2-D drafting.

IronCAD provides software generally for CADD in the manufacturing industry. IRONCAD is a 3-D solid modeling and 2-D drafting program with PDM functions. A third-party application offers simulation and FEA tools compatible with IRONCAD. INOVATE is a version of IRONCAD with fewer 3-D modeling functions and no 2-D drafting capabilities.

### Kubotek Corporation

Kubotek manufactures CADD and CAM software. KeyCreator is a 3-D solid modeling and 2-D drafting program generally for CADD in the manufacturing industry; it is the chief Kubotek product. Kubotek Validation Tool conﬁrms design accuracy during or after a speciﬁ c activity, such as a design revision or data translation. Kubotek also manufactures KeyMachinest for CAM and maintains CADKEY for 3-D wireframe modeling.

### Parametric Technology Corporation

Parametric Technology Corporation, or PTC, offers several software products generally focused on CADD in the manufacturing industry. Pro/ENGINEER is a 3-D solid modeling and 2-D drafting program and is the core PTC software. PTC provides various additions to the Pro/ENGINEER platform, including tools for CAE, CAM, and PDM: for example, Pro/ENGINEER Mechanica for simulation and FEA, Pro/ENGINEER Piping and Cabling Extension for pipe and cable design, and Pro/ENGINEER Reverse Engineering for automating reverse engineering. Reverse engineering is the process of converting an existing physical product into drawings or digital models, and it involves discovering the technological principles of a device, object, or system by analyzing its structure, function, and operation.

PTC manufactures other software, including Windchill for PDM, CoCreate for CAD, CAE, and PDM, and MathCAD for engineering calculations.

### Siemens Corporation

Siemens Corporation offers a wide variety of products and services. The Siemens PLM Solutions (www.plm.automation. siemens.com) brand manufactures PLM software. NX ad-dresses each area of product development, and it is the primary Siemens PLM Solutions software. NX provides tools for 3-D solid modeling, 2-D drafting, and speciﬁc applications such as tool and ﬁxture, routed system, and sheet metal product design. NX also offers simulation, FEA, CAM, and PDM functions. In addition to NX, Siemens PLM Solutions produces SolidEdge for 3-D solid modeling and 2-D drafting, generally for CADD in the manufacturing industry. The additional Siemens PLM Solutions brand software focuses on speciﬁ c aspects of PLM.

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# How Manual Drafting Equipment & Supplies used in CAD

## MANUAL DRAFTING

Manual drafting, also known as hand drafting, describes traditional drafting practice using pencil or ink on a medium such as paper or polyester film, with the support of drafting instruments and equipment. This chapter also explains drawing scale, sheet size, and sheet format.

Computer-aided design and drafting (CADD) has replaced manual drafting in most of the drafting industry.

As a result, some of the information in this chapter primarily serves as a historical reference. However, both manual drafting and CADD require that you understand the basics of drafting. Concepts such as scale, sheet size, and sheet format are critical and universal to manual drafting and CADD. Also, some companies use CADD but have manual drafting equipment available that you should be able to recognize and operate at a basic level.

### MANUAL DRAFTING EQUIPMENT AND SUPPLIES

Professional manual drafting requires appropriate drafting of equipment and supplies. If you work in a modern CADD environment, manual drafting tools such as compasses, dividers, triangles, templates, and scales have less importance. However, they are still valuable for sketching, taking measurements, and other related activities. You can purchase drafting supplies and equipment in a kit or buy items individually. Manual drafting equipment is available from many local and online vendors. Search the Internet or a phone book for keywords or headings such as drafting equipment and supplies, blueprinting, architect supplies, and artist supplies. Always purchase quality instruments for the best results. The following is a list of items generally needed for typical manual drafting:

• Drafting furniture.
• One 0.3 mm automatic drafting pencil with 4H, 2H, and H leads.
• One 0.5 mm automatic drafting pencil with 4H, 2H, H, and F leads.
• One 0.7 mm automatic drafting pencil with 2H, H, and F leads.
• One 0.9 mm automatic drafting pencil with H, F, and HB leads.
• Sandpaper sharpening pad.
• Erasers recommended for drafting with pencil on paper.
• Erasing shield.
• Dusting brush.
• 6 in. Bow compass.
• Dividers.
• 8 in. 30–60 triangle.
• 8 in. 45 triangle.
• Circle template with small circles.
• Circle template with large circles.
• Irregular curve.
• Scales:
• Triangular architect's scale.
• Triangular civil engineer's scale.
• Triangular metric scale.
• Drafting tape.
• Lettering guide (optional).
• Arrowhead template (optional).

### DRAFTING PENCILS AND LEADS

Automatic pencils are standard for manual drafting, sketching, and other office uses. The term automatic pencil refers to a pencil with a lead chamber that advances the lead from the chamber to the writing tip by the push of a button or tab when a new piece of lead needed. Automatic pencils hold leads of one width, so you do not need to sharpen the lead. The pencils are available in several different lead sizes.
Drafters typically have several automatic pencils. Each pencil has a different grade of lead hardness and is appropriate for a
specific technique. This reduces the need to change leads constantly. Some drafters use a light blue lead for layout work. If your primary work is CADD, a combination of 0.5-, 0.7-, and 0.9 mm pencils and leads is good for sketching and related activities.

Lead grades of 2H and H are good in your automatic pencil for typical daily office use. The leads you select for line work and lettering depend on the amount of pressure you apply and other technique factors. Experiment until you identify the leads that give the best line quality. Leads commonly used for thick lines range from 2H to F, whereas leads for thin lines range from 4H to H, depending on individual preference.
Construction lines for layout and guidelines are very lightly drawn with a 6H or 4H lead. The Figure shows the different lead grades.

### Compasses

A compass is an instrument used to draw circles and arcs. A compass is especially useful for large circles, but using one can be time-consuming. Use a template, whenever possible, to make circles or arcs more quickly.

There are several basic types of compasses. A bow compass, shown in Figure, is used for most drawing applications. A beam compass consists of a bar with an adjustable needle, and a pencil or pen attachment for swinging large arcs or circles. Also available is a beam that is adaptable to the bow compass. This adapter works only on a bow compass that has a removable leg.

### DIVIDERS

Dividers are used to transfer dimensions or to divide a distance into several equal parts. Dividers are also used in navigation to measure distance in nautical miles. Some drafters prefer to use bow dividers because the centre wheel provides the ability to make fine adjustments easily. Besides, the setting remains more stable than with standard friction dividers.

A functional divider should not be too loose or tight. It should be easy to adjust with one hand. You should always control a divider with one hand as you layout equal increments or transfer dimensions from one feature to another. Do not try to use a divider as a compass. The Figure shows how to handle the divider when used.

### Proportional Dividers

Proportional dividers are used to reduce or enlarge an object without having to make mathematical calculations or scale manipulations. The centre point of the divider is set at the correct point for the proportion you want. Then you measure the original size line with one side of the proportional divider; the other side automatically determines the new reduced or enlarged size.

### PARALLEL BAR

The parallel bar slides up and down a drafting board to allow you to draw horizontal lines. Use triangles with the parallel bar to draw vertical lines and angles. The parallel bar was common for architectural drafting because architectural drawings are frequently very large. Architects
using manual drafting often need to draw straight lines the full length of their boards, and the parallel bar is ideal for such lines.

### TRIANGLES

There are two standard triangles. The 30º–60º triangle has angles of 30–60–90. The 45 triangle has angles of 45–45–90. Some drafters prefer to use triangles in place of a vertical drafting machine scale, as shown in Figure. Use the machine protractor or the triangle to make angled lines. Using parallel bars, drafters utilize triangles to make vertical and angled lines.

Triangles can also be used as straightedges to connect points for drawing lines without the aid of a parallel bar or machine scale. Use triangles individually or in combination to draw angled lines in 15 increments Also available are adjustable triangles with built-in protractors that are used to make angles of any degree up to a 45 angle.

### TEMPLATES

Manual drafting templates are plastic sheets with accurate shapes cut out for use as stencils to draw specific shapes. The most common manual drafting templates are circle templates for drawing circles and arcs. Templates for drawing other shapes, such as ellipses, and for letters are also common. Templates are also available for specific requirements and drafting disciplines. For example, use architectural templates to draw the floor plan and other symbols to scale. Electronic drafting templates have schematic symbols for electronic schematic drawings.

### Circle Templates

Circle templates are available with circles in a range of sizes beginning with 1/16 in. (1.5 mm). The circles on the template are marked with their diameters and are available in fractions, decimals, or millimetres. Figure 2.10 shows the parts of a circle. A popular template is one that has circles, hexagons, squares, and triangles.

Always use a circle template rather than a compass. Circle templates save time and are very accurate. For best results, when making circles, keep your pencil or pen perpendicular to the paper. To obtain proper width lines with a pencil, use a 0.9 mm automatic pencil.

### Ellipse Templates

An ellipse is a circle seen at an angle. Isometric circles are ellipses aligned with the horizontal right or left planes of an isometric box. Isometric ellipse templates automatically position the ellipse at the proper angle of 35 16'.

### IRREGULAR CURVES

Irregular curves, commonly called French curves, are curves that have no constant radii. A radius curve is composed of a radius and a tangent. The radius on these curves is constant and ranges from 3 ft to 200 ft. (900–60,000 mm). Irregular curves are commonly used in highway drafting. Ship's curves are also available for layout and development of ships hulls. The curves in a set of ship's curves become progressively larger and, like French curves, have no constant radii. Flexible curves are also available that allow you to adjust to the desired curve.

### DRAFTING MACHINES

A manual drafting machine is a machine that mounts to the table or board and has scales attached to an adjustable head that rotates for drawing angles. When locked in a zero position, the scales allow drawing horizontal and vertical lines and perpendicular lines at any angle orientation. The drafting machine vernier head allows you to measure angles accurately to 5' (minutes). Drafting machines, for the most part, take the place of triangles and parallel bars. The drafting machine maintains a horizontal and vertical relationship between scales, which also serve as straightedges. A protractor allows the scales to be set quickly at any angle.

There are two types of drafting machines: arm and track. The track machine generally replaced the arm machine in the history of manual drafting. A major advantage of the track machine is that it allows the drafter to work with a board in the vertical position. A vertical drafting surface position is generally more comfortable to use than a horizontal table. When ordering a drafting machine, the speciﬁcations should relate to the size of the drafting board on which it is mounted. For example, a 37½ 3 60 in. (950–1500 mm) machine properly ﬁts a table of the same size.

#### Arm Drafting Machine

The arm drafting machine is compact and less expensive than a track machine. The arm machine clamps to a table and through an elbowlike arrangement of supports allows you to position the protractor head and scales anywhere on the board. The Figure shows an arm drafting machine.

#### Track Drafting Machine

A track drafting machine has a traversing arm that moves left and right across the table and a head unit that moves up and down the traversing arm. There is a locking device for both the head and the traversing arm. The shape and placement of the controls of a track machine vary with the manufacturer, although most brands have the same operating features and procedures.

### SCALES

A scale is an instrument with a system of ordered marks at ﬁxed intervals used as a reference standard in measurement. A scale establishes a proportion used in determining the dimensional relationship of an actual object to the representation of the same object on a drawing. Use speciﬁc scales for mechanical, architectural, civil, and metric drawings.

Manual drafters use scales as measurement instruments to help create scaled drawings. In a CADD work environment, a scale is useful for sketching and taking measurements, as well as for related tasks. The scale is a universal and critical design and drafting concept.

#### Scale Shapes

There are four basic scale shapes, as shown in Figure. The two-bevel scale is also available with chuck plates for use with standard arm or track drafting machines. Drafting machine scales have typical calibrations, and some have no scale reading for use as a straightedge. Drafting machine scales are purchased by designating the length needed—12, 18, or 24 in.—and the scale calibration such as metric, engineer's full scale in tenths and half-scale in twentieths, or architect's scale 1/4" 5 1' –0". Many other scales are available. The triangular scale is commonly used in drafting and has different scale calibrations on each corner of the triangle. Common triangular scales are the architectural scale calibrated in feet and inches, mechanical scale calibrated in decimal inches, civil scale calibrated in feet and tenths of a foot, and the metric-scale calibrated in millimetres and centimetres.

#### Drawing Scale

Drawings are scaled so that the objects represented can be illustrated clearly on standard sizes of paper. It would be difﬁcult, for example, to make a full-size drawing of a house. You must decrease the displayed size, or scale, of the house to ﬁt properly on a sheet. Another example is a very small machine part that requires you to increase the drawing scale to show necessary detail. Machine parts are often drawn full size or even two, four, or ten times larger than full size, depending on the actual size of the part.

The selected scale depends on:

• The actual size of the objects
• The amount of detail to
• The media size.
• The amount of dimensioning and notes

In addition, you should always select a standard scale that is appropriate for the drawing and drafting discipline. The drawing title block usually indicates the scale at which most views are drawn or the predominant scale of a drawing. If the scale of a view differs from that given in the title block, the unique scale typically appears as a note below the corresponding view.

#### Mechanical Engineer's Scale

The mechanical engineer's scale is commonly used for mechanical drafting when drawings are in fractional or decimal inches. The mechanical engineer's scale typically has full-scale divisions that are divided into 1/16, 10, and 50. The 1/16 divisions are the same as the 16 architect's scale where there are 12 in. and each inch is divided into 1/16 in. increments (or sometimes 1/32 in. divisions). The 10 scale is the same as the 10 civil engineer's scale, where each inch is divided into ten parts, with each division being .10 in. The 50 scale is for scaling dimensions that require additional accuracy because each inch has 50 divisions. This makes each increment 1/30 in. or .02 in. (1 4 50 5 .02). The Figure shows a comparison between the mechanical engineer's scales. The mechanical engineer’s scale also has half-size 1:2 (1/2" 5 1"), quarter-size 1:4 (1/4" 5 1"), and eighth-size 1:8 (1/8" 5 1") options for reducing the drawing scale (see Figure 2.28). Figure 2.29 on page 53 shows a drawing that is represented at full scale (1:1), half-scale (1:2), and quarter-scale (1:4) for comparison.

### DRAFTING MEDIA

The term media, as applied here, refers to the material on which you create drawings, such as paper or polyester ﬁlm. The two main types of media used for manual drafting are vellum and polyester ﬁlm, with vellum being the most commonly used. Several factors other than cost also inﬂuence the purchase and use of drafting media, including durability, smoothness, erasability, dimensional stability, and transparency.

Durability is a consideration if the original drawing will be extensively used. Originals can tear or wrinkle, and the images can become difﬁcult to see if the drawings are used often. Smoothness relates to how the medium accepts line work and lettering. The material should be easy to draw on so that the image is dark and sharp without a great deal of effort on your part.

Erasability is important because errors need to be corrected, and changes are frequently made. When images are erased, ghosting—the residue that remains when lines are dif- ﬁcult to remove—should be kept to a minimum. Unsightly ghost images reproduce in a print. Materials that have good erasability are easy to clean. Dimensional stability is the quality of the media to remain unchanged in size because of the effects of atmospheric conditions such as heat, cold, and humidity. Some materials are more dimensionally stable than others.

#### Reproduction

One thing most designers, engineers, architects, and drafters have in common is that their ﬁnished drawings are intended for reproduction. The goal of every professional is to produce drawings of the highest quality that give the best possible prints when reproduced. Many of the factors that inﬂuence the selection of media for drafting have been described; however, the most important factor in reproduction.

The primary combination that achieves the best reproduction is the blackest and most opaque lines or images on the most transparent base or material. Vellum and polyester ﬁlm make good prints if the drawing is well done. If the only concern is the quality of the reproduction, ink on polyester ﬁlm is the best choice. However, some products have better characteristics than others. Some individuals prefer certain products. It is up to individuals and companies to determine the combinations that work best for their needs and budgets.

### SHEET SIZE AND FORMAT

#### STANDARDS

Most professional drawings follow speciﬁc standards for sheet size and format. The Australian Drafting Standard specifies the exact sheet size and format for engineering drawings created for the manufacturing industry. Other disciplines can follow Australian Drafting standards. However, architectural, civil, and structural drawings used in the construction industry generally have a different sheet format and may use unique sheet sizes, such as architectural sheet sizes. Follow sheet size and format standards to improve readability, handling, ﬁling, and reproduction; this will also help ensure that all necessary information appears on the sheet.

When selecting a sheet size, consider the size of objects drawn; the drawing scale; the amount of additional content on the sheet, such as a border, title block, and notes; and drafting standards. In general, choose a sheet size that is large enough to show all elements of the drawing using an appropriate scale and without crowding. For example, the dimensioned views of a machine part that occupies a total area of 15 in. 3 6 in. (381 mm 3 153 mm), can typically ﬁt on a 17 in. 3 11 in.   (B size) or 420 mm 3 297 mm (A3 size) sheet.

### DIAZO REPRODUCTION

Diazo prints are also known as ozalid dry prints and blue-line prints. The diazo reproduction process has been mostly replaced by photocopy reproduction and the use of CADD ﬁles for printing and plotting. Diazo printing uses a process that involves an ultraviolet light passing through a translucent original drawing to expose a chemically coated paper or print material under-neath. The light does not go through the dense, black lines on the original drawing, so the chemical coating on the paper beneath the lines remains. The print material is then exposed to ammonia vapour, which activates the remaining chemical coat-ing to produce blue, black, or brown lines on a white or colour-less background. The print that results is a diazo, or blue-line print, not a blueprint. The term blueprint is a generic term used to refer to diazo prints even though they are not true blueprints. Originally, the blueprint process created a print with white lines on a dark blue background.

### PHOTOCOPY REPRODUCTION

Photocopy printers are also known as engineering copiers when used in an engineering or architectural environment. A photocopy printer is a machine for photographically reproducing material, especially by xerography. Xerography is a dry photographic or photocopying process in which a negative image formed by a resinous powder on an electrically charged plate is electrically transferred to and ﬁxed as a positive image on a paper or other copying surface. Prints can be made on bond paper, vellum, polyester ﬁ lm, coloured paper, or other translucent materials. The reproduction capabilities also include instant print sizes ranging from 45 percent to 141 percent of the original size.
Larger or smaller sizes are possible by enlarging or reducing in two or more steps. Almost any large original can be converted into a smaller-sized reproducible print, and then the secondary original can be used to generate additional photocopy prints for distribution, inclusion in manuals, or for more convenient handling. In addition, a random collection of mixed-scale drawings can be enlarged or reduced and converted to one standard scale and format. Reproduction clarity is so good that halftone illustrations (photographs) and solid or ﬁne line work have excellent resolution and density.
The photocopying process and CADD printing and plotting have mostly replaced the diazo process. Photocopying has many advantages over diazo printing, including quality repro-duction in many sizes, use of most common materials, and no hazardous ammonia. A CADD system allows you to produce a quality hard copy print quickly. A hard copy is a physical drawing produced by a printer or plotter. The hard copy can be printed on vellum for further reproduction using the diazo or photocopy process.

### PROPERLY FOLDING PRINTS

Prints come in a variety of sizes ranging from small, 8½ 3 11 in., to 34 3 44 in. or larger. It is easy to ﬁ le the 8½ 3 11 in. size prints because standard ﬁle cabinets are designed to hold this size. There are ﬁle cabinets available called ﬂat ﬁles that can be used to store full-size unfolded prints. However, many companies use standard ﬁle cabinets. Larger prints must be properly folded before they can be ﬁled in a standard ﬁle cabinet. It is also important to fold a print properly if it is to be mailed.
Folding large prints is much like folding a road map. Folding is done in a pattern of bends that results in the title block and sheet identiﬁ cation ending up on the front. This is desirable for easy identiﬁ cation in the ﬁle cabinet. The proper method used to fold prints also aids in unfolding or refolding prints.

### MICROFILM

Microfilm is photographic reproduction on ﬁlm of a drawing or other document that is highly reduced for ease in storage and sending from one place to another. When needed, equipment is available for enlargement of the microﬁ lm to printed old vellum becomes yellowed and brittle. In addition, in case of a ﬁre or other kind of destruction, originals can be lost and endless hours of drafting vanish. For these and other reasons, microﬁlm has been used for storage and reproduction of original drawings. Although microﬁlm storage of old drawings still exists in some companies, CADD ﬁles have replaced the use of microﬁlm for most modern applications.

### CADD VERSUS MICROFILM

Microﬁlm was once an industry standard for storing and accessing drawings. Large international companies especially relied on the microﬁlm network to ensure that all worldwide subcontractors, vendors, clients, and others involved with a project were able to reproduce needed draw-ings and related documents. One advantage of microﬁlm was the ability to archive drawings—that is, store some-thing permanently for safekeeping.
The use of CADD in the engineering and construction industries has made it possible to create and store drawings electronically on a computer, optical disk, or other media. This makes it possible to retrieve stored drawings easily and quickly. A big advantage of CADD ﬁle storage involves using CADD drawings. When you retrieve CADD-generated drawings, they are of the same quality as when they were originally drawn. You can use CADD drawings to make multiple copies or to redesign a product efﬁciently. In addition to the maintained original quality of the stored CADD drawing, the drawing ﬁle can be sent anywhere in the world over the Internet or within a company's intranet. The Internet is a worldwide network of communication between computers, and intranet links computers within a company or an organization.

The optimum efﬁciency of design and manufacturing methods is achieved without producing a single paper copy of a drawing of a part. Computer networks can directly link engineering and manufacturing departments by integrating computer-aided design (CAD) and computer-aided manufacturing or machining (CAM) software. This integration is referred to as CAD/CAM. The drafter or designer creates a 3-D model or 2-D engineering drawing of a part using CADD software. CAM software is then used to convert the geometry to computer numerical control (CNC) data that is read by the numerically controlled machine tools. Often, the CAD/CAM system is electronically connected to the machine tool. This electronic connection is called networking. This direct link is referred to as direct numerical control (DNC), and it requires no additional media such as paper, disks, CDs, or tape to transfer information from engineering to manufacturing.

# Facts of the Drafting Professional Perspective

## PROFESSIONAL PERSPECTIVE

There is a significant difference between an individual trained in the theories, principles, standards, and requirements of the career ﬁeld and a true professional. Being a professional is more than holding a credential. A certiﬁcate or diploma is only an indication of knowledge in the area you have chosen to study. Many recently educated people search for a large salary, but they generally have only a moderate understanding of their career ﬁeld and little or no training as a true professional.

The facts are simple. When employed, you typically sign an agreement indicating job requirements, work times, vacations, sick days, insurance provisions, and employer expectations.

Many employers have a dress code, a code of ethics, and other provisions you must follow. As an employee, you are an adult who is being paid to make things happen. You are a part of a working machine, but you are not the main wheel that makes it turn. Do your job, do it well, and keep the wheels turning, which is your primary function in an entry-level position.

In becoming a true professional, you need to keep in mind that with the availability of the Internet and other media, that your potential employer can check up on you and in many cases ﬁnd out more than you want them to know. Facebook, MySpace, blogs, and other social networking areas on the Internet can be very damaging to your career if misused. As with your professional attitude, you need to keep some things private.

## PROFESSIONAL NETWORK

You do need a professional network, and there are many of them such as LinkedIn or Plaxo that can help you network on a professional level. Now is the time to exhibit responsibilities to yourself and your employer.

In my current role, I am in constant contact with the leaders of the industry, representing some of the most prestigious manufacturing, engineering, architectural, and industrial ﬁrms in the world. When discussing the employment of future drafters and designers, I often request information on the reasons one individual is chosen over another when they are equally qualiﬁed. The answer is consistent; they employ those who reﬂect professionalism in all aspects of their individuality and areas of training.

## PROFESSIONAL FACTS

The following are 15 facts that make you a professional:

1. You must understand that your education begins after you have achieved your Your credentials only expose you to the knowledge and skills needed to perform the job. Real learning comes from day-to-day experience over many years.
2. Consider the interview process, the interviewer, and the type of company when seeking to Investigate the company and determine what they do, their geographic area, and who owns the company. The company mission and employee expectations should match your goals and objectives.
3. If you are seeking a career, do not take a job just to be Dissatisfaction may show in your work and performance, and it may result in you seeking new employment or being terminated. Employment changes can make it difﬁcult to becoming reemployed. You should always keep a position for two or more years.
4. Leave your attitude at You should show gratitude for your employment. Be proud that this company thinks you have the potential to be a part of its working family. Keep in mind that you are not the owner.
5. Keep your opinion to yourself, focus on your job, and shape your This will bring you more attention and give you more excellent opportunities. Share improvement ideas with your supervisor. Ask if your work is acceptable and if there is anything that you can do better. Accept criticism with modesty.
6. Many co-workers will do anything to advance, which is an unethical fact of survival in This activity can lead to discontent. Remember, you work for your supervisor, your job is to improve the product, produce a product, and increase company proﬁts. Negative actions toward you by co-workers reﬂect their own inability to carry out their duties.
7. Acting professional is a big part of your new You hold credentials, and with them comes a code of ethics that professionals follow. Here are some guidelines: (1) Be at your workstation, the computer turned on, chair adjusted, and ready to work a few minutes before work time. (2) Take your breaks at the designated. This is when you typically go to the restroom, get a coffee reﬁll, or eat a snack. Work time is for production. (3) Your scheduled lunchtime includes You may ﬁnd it more convenient to eat at work and have time to relax or do personal things. (4) Quitting time can be exciting, but do not stop early just to be out the door at 5 P.M. sharp. Complete a project and then deliver it to your supervisor if it takes a few minutes. You will have a head start on tomorrow and your career.
8. Dress well for your interview and on the job, providing a professional Men should wear a shirt and tie, jacket, dress pants, and polished leather shoes with laces. Women should wear professional style clothing, ﬁtting to the employment atmosphere. Women should avoid wearing dresses for the interview. Women should wear dress pants or a skirt, blouse, and matching jacket, or a pants suit, and avoid necklines more than four ﬁngers below the high point of your sternum. Patent leather or athletic shoes should not be worn by either sex. Shoes should coordinate with your clothing and should be ﬂats or low heels. Avoid noisy shoes. Wear professional colour such as navy, black, or grey. Do not wear a white, yellow, or chartreuse jacket. Your shirt or blouse should be white, light blue, or a pastel colour. Men should wear a tie that coordinates with the jacket and pants and wear a belt that matches shoe colour. In today’s liberal workforce, unisex clothing is readily available, and some of it looks sharp. However, in the interview process, make sure your clothing is cut to ﬁt your body style. Accessories should be moderate, with no visible necklaces or dangling earrings. Cologne and perfume should be very subdued. For men and women, exposed body piercings in your nose, lips, and tongues and multiple sets of earrings should not be worn at the interview.
9. Personal choices should be used on personal time or when found to be acceptable. Otherwise, you could jeopardize your employment opportunity. Keep in mind, you are applying for a job, and you do not know the preference of the company or the interviewer. The company makes the rules. Do not try to change policy if you want to keep your place. Observe the company dress code, so you know how to dress when you are employed.As a new hire, you should dress conservatively even if you see others are wearing jeans and polo shirts. If every- one wears shirts and ties, you do the same and make sure you have a jacket. Having a jacket or sport coat is good in case you need to attend a meeting. If the job requires you to go to manufacturing or to the ﬁeld, you should have an appropriate change of clothes or cover-up. Finally, regardless of the dress code, keep a change of clothes in your car and be ready for an emergency dress up or dress down in a few minutes.
10. Self-improvement is a good investment in the job. Research on work, processes, clients, and another project-related issue while on your own time. This can improve your production, broaden your mind, discover new project ideas, ﬁnd software solutions and production methods, or network with other professionals.
11. Most employment communication is proprietary and should not be discussed with anyone other than your supervisor or involved co-workers. Do not take information from work to home, unless approved by your supervisor.
12. Write personal e-mails and make personal phone calls after work or on your personal cell phone outside the of- ﬁce during break or at lunch. Using company equipment and company time is only for company business.
13. After employment, you need to start preparing for you next move up the career ladder. Your employer may offer educational beneﬁts. If you have access to the Internet at home, you can do webinars and take online training and technical training or expand your formal education. Your new knowledge, ability to speak on the technical subjects, and performance at work indicate your improvement without bragging. Provide information about your expanded learning during your annual reviews.
14. Completion of your education is only one step in the overall progression of your career track. You should seek industry certiﬁcation with a professional organization. Certiﬁcation is based on industry standards and required knowledge at a speciﬁc level in the profession, and it is offered by industry organizations who are experts in the ﬁeld. Certiﬁcation competencies provide minimum performance and knowledge levels to your employer. Certiﬁcations can be related to software, codes, standards, technical writing, and other subjects. Additional training reinforces your abilities and your employability.
15. Keep a work journal as an organizational tool and to improve your growth as a professional. Include speciﬁc assignment information, assignment performance, individuals involved, speciﬁc times and places related to the assignment, when you go to lunch, change projects, talk to a co-worker about a previous project, or attend a meeting about a new project. Entries made by time and date will stand ﬁrm in a challenge. The more you document, the better.
16. While in school and after, you should be a member of any professional organization that relates to your profession. ADDA and Skills USA offer student memberships for the drafting profession. By being involved in professional associations, you will ﬁnd a network of professionals who can assist you in every phase of your career path and offer opportunities, advice, and guidance you cannot receive anywhere else. As you leave your school and enter the workforce, you should retain your membership in the professional organization and become as active as possible.

Most organizations provide you with professionally rewarding volunteer opportunities on committees and groups to assist the profession. As you gain experience, you will see yourself working on projects with little assistance, moving up the corporate steps, being given more responsibility and increased compensation, and having opportunities you hoped for when you were ﬁrst employed.

## SUMMERY

The following summarizes our profession:

Drafting is the foundation and stepping-stone of any aspiring architect and engineer. It is a tedious profession, with days ﬁlled with non- stop drawing and making models of designs. It is through this process that one is able to learn to develop new skills and be introduced to styles that can be used as inspiration for personal design preferences in the future. Drafting moulds the builders and designers of the future. Drafting is the profession of the hardworking and the persevering, the patient and the creative, the ambitious and the proud.

# CAD DRAFTER, THEIR EDUCATION & JOB OPPORTUNITIES

## THE CAD DRAFTER

The term drafter commonly refers to a man or woman who is employed in the drafting profession. Other general-purpose titles include draftsperson, design drafter, drafting technician, engineering drafter, CADD operator, and CADD technician. A job title can also be discipline or task speciﬁc. For example, a cad drafter who works for a civil engineering ﬁrm is a civil drafter, civil engineering drafter, construction drafter, or civil CADD technician. Several industries and most engineering and architectural related ﬁelds require drafters.

According to the Australian Department of Labor, most drafters work in the following industries:

• Professional, scientiﬁc, and technical services.
• Manufacturing
• Construction
• Administrative and support services.

Drafters prepare technical drawings and plans used by production and construction workers to build everything from microchips to skyscrapers. Drafters’ drawings provide visual guidelines and show how to construct a product or structure. Drawings include technical details and specify dimensions, materials, and procedures. Drafters ﬁll in technical details using drawings, rough sketches, speciﬁcations, and calculations made by engineers, surveyors, architects, or scientists. For example, many drafters use their knowledge of standardized building techniques to draw Notice edit the details of structures.

Most drafters use CADD systems to prepare drawings. Accordingly, some drafters may be referred to as CADD operators. With CADD systems, drafters can create and store drawings electronically so that they can be viewed, printed, or programmed directly into automated manufacturing systems. CADD systems also permit drafters to prepare variations of a design quickly. Although drafters use CADD extensively, they still need knowledge of traditional drafting techniques in order to fully understand and explain concepts. Some use their understanding of engineering and manufacturing theory and standards to draw the parts of a machine; they determine design elements, such as the numbers and kinds of fasteners needed to assemble the machine. Drafters use technical handbooks, tables, calculators, and computers to complete their work.

## DRAFTING FIELDS

Drafting is a broad occupation. There are many drafting ﬁelds and several drafting or related occupations within each ﬁ eld. The most common drafting ﬁelds include architecture, civil and electrical engineering, electronics, mechanical engineering, and industrial process-pipe drafting.

Drafting, in general, has one basic description, but speciﬁc drafting areas have unique conceptual and skill characteristics. Drafters perform general duties described under the title of drafter in all drafting disciplines. Most drafters rely on knowledge of engineering or architectural principles, mathematical formulas, physical laws, and manufacturing or construction processes and limitations.

Drafters typically work from analyzes, standards, speciﬁ cations, sketches, engineering drawings, models, prototypes, verbal instructions, ideas, and related design data. Drafters then perform discipline and project speciﬁc tasks that require certain knowledge and skill. For example, an automotive design drafter requires knowledge of automotive vehicle design and manufacturing.
Drafters often create a variety of drawings even though they may be employed in a certain ﬁ eld or focus on a speciﬁc product. For example, an architectural drafter may be involved in preparing structural, electrical, plumbing, and civil drawings.

A mechanical drafter may participate in simulation and analysis studies and create electronic drawings and technical illustrations. Drafters often work with a team, individuals of the same discipline, and others related to a speciﬁc project. For example, architectural drafters typically work with architects, architectural designers, and related architecture, engineering, and construction professionals.

### Aeronautical Cad Drafter

Aeronautical drafting is a specialization of mechanical drafting. Aeronautical drafters may create CADD models and drawings of aeroplanes, missiles, spacecraft, and components and related equipment, such as launch mechanisms.

### Architectural Cad Drafter

Architectural drafters prepare CADD models and drawings of the architectural and structural features of a building. The figure is an example of an architectural elevation. The figure shows examples of architectural details. Architectural drafters rely on knowledge of building materials, codes, construction methods, and engineering practices. Architectural drafters work from speciﬁcations, sketches, and rough drafts. Architectural drafters may specialize in a type of building, such as residential or commercial, or construction material, such as reinforced concrete, masonry, steel, or timber.

### Automotive Design Cad Drafter

Automotive design drafting is a specialization of mechanical drafting. Automotive design drafters develop working layouts and master drawings of automotive vehicle components, assemblies, and systems.

### Casting, Forging, and Mold Cad Drafter

Casting, forging, and mould drafting is a specialization of mechanical drafting. Casting, forging, and mould drafters create CADD models and drawings for castings, forgings, and modelled parts. Castings, forgings, and moulded parts require special knowledge and attention to die and mould design, shrinkage allowances, and various other factors such as corner radii.

### Civil Cad Drafter

Civil drafters prepare CADD models and drawings used in construction or civil engineering projects, such as highways, bridges, pipelines, ﬂood-control projects, and water and sewage systems. The figure shows an example of a civil subdivision plan. Civil drafters create topographical and relief maps, and plot maps and charts showing proﬁles and cross-sections, indicating the relation of topographical contours and elevations to buildings, retaining walls, tunnels, overhead power lines, and other structures.

Civil drafters prepare detailed drawings of structures and installations, such as roads, culverts, fresh-water supplies, sewage-disposal systems, dikes, wharves, and breakwaters.

Civil drafters also compute the volume of the tonnage of excavations and ﬁlls and prepare graphs and hauling diagrams used in earthmoving operations. Civil drafters may accompany survey crew in ﬁeld to locate grading markers or to collect data required for revision of construction drawings. A topographical drafter is a civil drafter who specializes in drafting and modifying topographical maps from surveying notes and aerial photographs.

### Cartographic Cad Drafter

A cartographic drafter, also known as a cartographer, draws maps of geographical areas to show natural and constructed features, political boundaries, and other features. Cartographers collect, analyze, and interpret geographic information provided by geodetic surveys, aerial photographs, and satellite data. Cartographers research, study and prepare maps and other spatial data in digital or graphic form for legal, social, political, educational, and design purposes. Cartographers may also work with and develop a geographic information system (GIS).

### Commercial Cad Drafter

Commercial drafting is a specialization of architectural drafting. A commercial drafter, also known as a facilities drafter, is responsible for laying out the location of buildings, planning the arrangements of ofﬁces, large rooms, store buildings, and factories, and drawing charts, forms, and records. A commercial drafter may also create 3-D rendered models.

### Directional Survey Cad Drafter

Direction survey drafting is a specialization of civil drafting. Directional survey drafters plot oil- or gas-well boreholes from photographic subsurface survey recordings and other data. Directional survey drafters compute and represent diameter, depth, degree, and direction of inclination, location of equipment, and other dimensions and characteristics of boreholes.

### Electrical Cad Drafter

Electrical drafters generate CADD models and drawings of electrical equipment, wiring diagrams, circuit board assembly diagrams, and layout drawings used by construction crews and repairers who erect, install, and repair electrical equipment and wiring in communications centres, power plants, industrial establishments, commercial and domestic buildings, and electrical distribution systems. An electric-cable diagrammer is an electrical drafter who specializes in preparing detail cable layout and diagrams for cable installation.

### Electronic Cad Drafter

Electronic drafters produce CADD models and drawings, such as wiring diagrams, layout drawings, mechanical detail drawings, and drawings of intermediate and ﬁnal assemblies that are used in manufacturing, assembling, installing, and repairing electronic devices and components, printed circuit boards, and equipment. Electronic drafters examine electronic schematics and supporting documents received from design engineering departments to develop, compute, and verify speciﬁcations in drafting data, such as conﬁguration of parts, dimensions, and tolerances.

### Geological Cad Drafter

Geological drafters draw maps, diagrams, proﬁles, cross-sections, directional surveys, and subsurface formations to represent geological or geophysical stratigraphy and locations of gas and oil deposits. Geological drafters correlate and interpret data obtained from topographical surveys, well logs, and geophysical prospecting reports and use special symbols to denote geological and geophysical formations or oil ﬁeld installations.

### Geophysical Cad Drafter

Geophysical drafters draw subsurface contours in rock formations from data obtained by geophysical prospecting. Geophysical drafters plot maps and diagrams from computations based on recordings of seismographs, gravity meters, magnetometers, and other petroleum-prospecting instruments and from prospecting and surveying ﬁeld notes. Geophysical drafters some- times receive a title such as a seismograph drafter, according to a speciﬁc method of prospecting.

### Heating, Ventilating, and Air-Conditioning Cad Drafter

Heating, ventilating, and air-conditioning drafters generally work for an HVAC engineering ﬁrm developing contract documents from engineering schematics. HVAC drafting may involve light design work in sizing and routing systems to conform to the allotted space with the building structure, as well as calculating heat loss and heat gain for buildings for use in determining equipment speciﬁcations. HVAC drafting may also involve trade-to-trade coordination on an elemental level.

A refrigeration drafter specializes in drawing plans for the installation of refrigeration equipment. A detail drafter, or detailer, works for an HVAC contractor developing 3-D models, detailed shop and installation drawings, performing trade-to-trade coordination to a ﬁnished degree and developing fabrication cut sheets. Detailers can also be involved in download to or input into a sheet metal fabrication software program.

### Industrial Process-Pipe Cad Drafter

An industrial process-pipe drafter—also known as an industrial pipe drafter, a piping drafter, and a pipeline drafter— prepares CADD models and drawings used in the layout, construction, and operation of oil and gas ﬁelds, reﬁneries, chemical plants, and process piping systems.

Industrial process-pipe drafters develop detail drawings for the construction of equipment and structures, such as drilling derricks, compressor stations, and gasoline plants; frame, steel, and masonry buildings; piping manifolds and pipeline systems; and for the manufacture, fabrication, and assembly of machines and machine parts.

Industrial process-pipe drafters prepare maps to represent geological stratigraphy, pipeline systems, and oil and gas locations, using ﬁeld survey notes, geological and geophysical prospecting data, and aerial photographs.

An oil and gas drafter is an industrial process-pipe drafter who specializes in oil and gas industrial pipe drafting.

### Landscape Cad Drafter

Landscape drafters prepare CADD models and drawings from rough sketches or other data provided by landscape architects. Landscape drafters may prepare separate detailed site plans, grading and drainage plans, lighting plans, paving plans, irrigation plans, planting plans, and drawings and details of garden structures. Landscape drafters may build models of proposed landscape construction and prepare coloured drawings for presentation to clients.

### Mechanical Cad Drafter

The manufacturing industry uses mechanical drafting, its name derived from mechanisms. The construction industry also uses mechanical drafting, but the term refers to drafting HVAC systems, which is the mechanical portion of an architectural project.

In general, mechanical drafting is the core of the engineering drafting industry. The terms engineering drawing and engineering drafting used throughout all drafting disciplines.

A mechanical drafter, also known as an engineering drafter, is a drafter associated with mechanical drafting for the manufacturing industry.

Mechanical drafters create CADD models and drawings of machinery and mechanical devices, indicating dimensions and tolerances, fastening and joining methods, and other engineering data and requirements. Mechanical drafters draw multiple-view part, assembly, subassembly, and layout drawings as required for manufacture and repair of machines and equipment. The figure shows an example of a part drawing.

### Marine Cad Drafter

Marine drafting is a specialization of mechanical and structural drafting. Marine drafters develop CADD models and drawings of structural and mechanical features of ships, docks, and other marine structures and equipment.

### Patent Cad Drafter

Patent drafters prepare clear and accurate drawings of varied sorts of mechanical devices for use of a patent lawyer in obtaining patent rights. The “Patents” section toward the end of this chapter provides additional information on patents and patent drawings.

### Photogrammetrist

Photogrammetrists analyze source data and prepare mosaic prints, contour-map proﬁ le sheets, and related cartographic materials that require technical mastery of photogrammetric techniques and principles.

Photogrammetrists prepare original maps, charts, and drawings from aerial photographs and survey data and apply standard mathematical formulas and photogrammetric techniques to identify, scale, and orient geodetic points, estimations, and other planimetric or topographic features and cartographic detail.

Photogrammetrists graphically represent aerial photographic detail, such as contour points, hydrography, topography, and cultural features, using precision stereo plotting apparatus or drafting instruments.

Photogrammetrists revise existing maps and charts and correct maps in various states of compilation. Photogrammetrists also prepare rubber, plastic, or plaster 3-D relief models.

### Plumbing Cad Drafter

A plumbing drafter, also known as a pipe drafter, specializes in CADD models and drawings for installing plumbing and piping equipment in residential, commercial, and industrial settings. Commercial and industrial piping relate closely to industrial process-pipe drafting.

### Structural Cad Drafter

Structural drafters create CADD models and drawings for structures that use reinforcing steel, concrete, masonry, wood, and other structural materials. Structural drafters produce plans and details of foundations, building frame, ﬂoor and roof framing, and other structural elements.

A detail drafter, or detailer, works for a structural contractor developing 3-D models, detailed shop drawings, and installation drawings, performing trade-to-trade coordination to a ﬁnished degree, and developing fabrication drawings. Detailers may also be involved in downloading to or inputting into a structural component fabrication software.

### Technical Illustrator

Technical illustrators layout and draw illustrations for reproduction in reference works, brochures, and technical manuals dealing with assembly, installation, operation, maintenance, and repair of machines, tools, and equipment.

Technical illustrators prepare drawings from blueprints, design mockups, and photographs by methods and techniques suited to speciﬁed reproduction process or ﬁnal use, photo-offset, and projection transparencies, using drafting and optical equipment.

Technical illustrators create schematic, perspective, axonometric, orthographic, and oblique-angle views to depict functions, relationships, and assembly sequences of parts and assemblies such as gears, engines, and instruments.

Technical illustrators also create rendered drawings and 3-D models, and they may draw cartoons and caricatures to illustrate operation, maintenance, and safety manuals and posters.

### Tool-and-Die Design Cad Drafter

Tool-and-die design drafting is a specialization of mechanical drafting. Tool-and-die design drafters prepare CADD models and detailed drawing plans for manufacturing tools, usually following designs and speciﬁcations indicated by tool designers.

## EDUCATION AND QUALIFICATIONS

The design and drafting profession can provide a rewarding career for people who enjoy detailed work and have a mechanical aptitude and ability to visualize. Math and communication skills are also important. The following information describes education and qualiﬁcation requirements for an entry-level drafting position.

High school courses in mathematics, science, computer technology, design, computer graphics, and drafting are useful for people considering a drafting career. However, employers in the drafting industry prefer applicants who have at least two years of postsecondary training in a drafting program that provides strong technical skills and considerable experience with CADD systems.

Employers are most interested in applicants with a strong background in fundamental drafting principles;well-developed drafting skills; knowledge of drafting standards, mathematics, science, and engineering technology; a solid background in CADD techniques; and the ability to apply their knowledge to a broader range of responsibilities. Future students should contact prospective employers to ask which schools they prefer and contact schools to ask for information about the kinds of jobs their graduates have, the type and condition of instructional facilities and equipment available, and teacher qualiﬁcations.

Many technical institutes, community colleges, and some four-year colleges and universities offer drafting programs. Technical institutes offer intensive technical training, but they provide a less general education than do community colleges Technical institutes may award either certiﬁcates or diplomas and programs can vary considerably in length and in the types of courses offered.

Many technical institutes offer two-year associate degree programs. Community colleges offer programs similar to those in technical institutes but include more classes in drafting theory and also often require general education classes. After completing a two-year associate degree program, graduates may obtain jobs as drafters or continue their education in a related ﬁeld at a four-year college. Most four-year colleges do not offer training in drafting, but they do offer classes in engineering, architecture, and mathematics that are useful for obtaining a job as a drafter. Technical training obtained in the armed forces can also apply in civilian drafting jobs. Some additional training may be necessary, depending on the technical area or military specialty.
Mechanical drafting—the type of drafting done for the manufacturing industry—offers the fundamental standards involved in the design and drafting profession. However, there are a variety of design and drafting discipline categories. Training differs somewhat within the drafting specialties, although the basics, such as mathematics, are similar. In an electronics drafting program, for example, students learn how to show electronic components and circuits in drawings. In architectural drafting, students learn the technical speciﬁ cations of buildings.

Some educational programs provide training in speciﬁ c disciplines, whereas others provide diversiﬁ ed training in several areas. The opportunity to experience more than one discipline allows you to ﬁnd an industry that you prefer.

### General Qualiﬁcations and Certiﬁcation

Mechanical ability and visual aptitude are important for drafters. Prospective drafters should be able to perform detailed work accurately. Artistic ability is helpful in some specialized ﬁelds, as is knowledge of manufacturing and construction methods. In addition, future drafters should have good interpersonal skills because they work closely with engineers, surveyors, architects, and other professionals and sometimes with customers.

Opportunities for advancement for drafters are excellent, although dependent on the advancement possibilities of a speciﬁc employer. Advancement also depends on your skill, initiative, ability, product knowledge, attitude, ability to communicate, continued education, and enthusiasm.

Entry-level or junior drafters usually do routine work under close supervision. After gaining experience, drafters may become intermediate drafters and progress to more difﬁcult work with less supervision. At the intermediate level, drafters may need to exercise more judgment and perform calculations when preparing and modifying drawings. Drafters may eventually advance to senior drafter, designer, or supervisor.

An entry-level drafting position may not be in your chosen ﬁeld, but you should be able to ﬁnd employment in your desired area with experience and an open job market. Opportunities are available that allow people to expand career potential into related areas such as tool design and cartography. Many people who enter the drafting industry begin to move up quickly into the design, checking, purchasing, estimating, and management.

Many employers pay for continuing education. Additional education for advancement usually includes increased levels of mathematics, pre-engineering, engineering, software, and advanced drafting. Appropriate college degrees may allow drafters to go on to become engineering technicians, engineers, or architects. Drafting has traditionally been an excellent way of designing, engineering, and management.

## DRAFTING JOB OPPORTUNITIES

Drafting job opportunities, which include all possible drafting employers, ﬂuctuate with national and local economies. Employment as a drafter remains tied to industries that are sensitive to cyclical changes in the economy, primarily construction and manufacturing.

A slowdown or speedup in construction and manufacturing nationally affects the number of drafting jobs available. The economic effect on drafting job opportunities also occurs at the local level or with speciﬁc industries. For example, construction may be strong in one part of the country and slow in another, so the demand for drafters in those localities is strong or slow accordingly.

Fewer drafters are required when large manufacturers, such as automobiles, experience poor sales. More drafters are required when industries such as high-tech expand. In addition, a growing number of drafters should continue to ﬁnd employment on a temporary or contract basis as more companies turn to the employment services industry to meet their changing needs.

Local demands also generally control the types of drafting jobs available. Each local area usually has a need for more of one type of drafting skill than another. In general, metropolitan areas where manufacturing is strong offer more mechanical drafting jobs than rural areas, which typically offer more civil or structural drafting jobs than other disciplines. Drafting curriculums in different geographical areas usually specialize in the ﬁelds of drafting that help ﬁll local employment needs.

A broader range of opportunities exists in many local areas because of the ﬂexibility of electronic data transfer, making it possible to complete tasks worldwide. Some drafting programs offer a broad-based education so graduates can have versatile employment opportunities. When selecting a school, research curriculum, placement potential, and local demand. Talk to representatives of local industries for an evaluation of the drafting curriculum.

### SEARCHING FOR A DRAFTING POSITION

Entry-level drafting positions require you to be prepared to meet the needs and demands of the industry. Entry into the drafting career marketplace depends on your training and ability and on the market demand. Your training, skills, and personal presentation are especially important in a poor economic environment, and these can make the difference in ﬁnding an employment opportunity.

A two-year, postsecondary degree in drafting can also provide a big advantage when seeking a position in the drafting industry. Programs of this type normally have a quality cross-section of training in design and drafting, math, and communication skills. Two-year, postsecondary drafting programs often have a job- preparation and placement services to aid their graduates.

Many of these schools have direct industry contacts that help promote hiring opportunities. Training programs also often have cooperative work experience (CWE) or internships in which their students work in the industry for a designated period while completing degree requirements.

These positions allow a company to determine if the student is a possible candidate for full-time employment and provide the student with valuable on-the-job experience to include on a résumé. Even if you do not go to work for the company where you do CWE or an internship, you can get a letter of recommendation for your portfolio.

When the local economy is doing well and drafting job opportunities are plentiful, it may be possible to ﬁnd a job with less than a two-year college degree. If you want to ﬁnd entry-level employment in a job market of this type, you can take intensive training in CADD practices. The actual amount of training required depends on how well you do and whether you can match an employer who is willing to hire with your level of training. Many people have entered the industry in this manner, although you would be well advised to continue schooling toward a degree while you are working.

### Job-Seeking Strategy

The following are some points to consider when you are ready to seek employment:

• Get your résumé in Take a résumé-preparation course or get some help from your instructors or a career counsellor. Your résumé must be quality and professional representation of you. When an employer has many résumés, the best stands out.
• Write an application or cover letter. You can receive help with an application or cover letter from the same people who help with your résumé. Write a professional and clear application letter that is short, to the point, and lists the reasons why you would be an asset to the company.
• Prepare a portfolio. Your portfolio should contain examples of school and industry drawings that you have Neatly organize the drawings and select examples that help you target the speciﬁc industry discipline that you are seek- ing. For example, include mechanical models and drawings if you are interviewing with a company in the manufacturing industry. Display architectural models and drawings if you are interviewing with an architect or building designer. Include letters of recommendation from employers and instructors with your portfolio.
• Register with the department, school, and state employment service. Watch the employment ads in local newspapers and check out Internet employment sites.
• Make a realistic decision about the type of place where you want to work and the salary and beneﬁts you really think you should Base these decisions on sound judgment. Your instructors should have this information for the local job market. Do not make salary your ﬁrst issue when seeking a career position. The starting salary is often just the beginning of many companies. Consider advancement potential. A drafting technology position often is a stepping- stone to many opportunities, such as design, engineering, and management.
• Research prospective companies to learn about their business or The Internet is a good place to seek information because most companies have a Web site. This type of research can help you during an interview.
• Be prepared when you get First impressions are critical. You must look your best and present yourself well. Always be on time or early. Relax as much as you can. Answer questions clearly and to the point, but with enough detail to demonstrate that you know what you are talking about. It is often unwise to talk too much. Show off your portfolio. Be prepared to take a CADD test or demonstrate your skills.
• Ask intelligent questions about the company during an interview because you need to decide if you want to work, For example, you may not want to work for a company that has no standards, poor working conditions, and pirated software. You might prefer to work for a company that has professional standards and CADD systems, a pleasant work environment, and advancement possibilities.
• Respond quickly to job The employment marketplace is often very competitive. You need to be prepared and move quickly. Follow whatever instructions an employer gives for you to apply. Sometimes employers want you to go in person to ﬁll out an application, and sometimes they want you to e-mail, fax, or mail a résumé. Either way, you can include your application letter and résumé. Sometimes employers want you to call for a preinterview screening.
• In an active economy, it is common to get more than one If you get an offer from a company, take it if you have no doubts. However, if you are uncertain, ask for 24 or 48 hours to make a decision. If you get more than one offer, weigh the options carefully. There are advantages and disadvantages to every possibility. Make a list of the advantages and disadvantages of each company for careful consideration.

### Employment Opportunities on the Internet

The Internet is a valuable place to seek employment. There are hundreds of Web sites available to help you prepare for and ﬁnd a job. Many Web sites allow you to apply for jobs and post your resume for possible employers.

Some employers screen applicants over the Internet. The only caution is that any Internet-displayed personal information is available for anyone to read. However, some Web sites such as www.seek.com.au provide a safe place to post your résumé for only employers to review. You should always conﬁrm that the terms of the agreement provide you with a safe place to search for employment.

## DRAFTING SALARIES AND WORKING CONDITIONS

Salaries in drafting professions are comparable to salaries of other professions with equal educational requirements. Employment benefits vary according to each employer. However, most employers offer vacation and health insurance coverage, and some include dental, life, and disability insurance.

# Importance of Reusability in CADD

Reusability is one of the important advantages of CADD. With CADD, it is never necessary to draw anything more than once. Developing a CADD symbols library further enhances the ability to reuse content. Building a parts library for reusability has increased productivity, decreased development costs, and set the highest standards for quality at the Test and Measurement Documentation Group at Tektronix, Inc. The parts library began by reusing 3-D isometric parts created by the CADD illustrator and saved as symbols in a parts library directory. By pathing the named symbols back to this library directory, each symbol becomes accessible to any directory and drawing ﬁle. This allows the CADD illustrator to insert library symbols into any drawing by selecting named symbols from the directory.

The illustrator adds new parts to the library as a product is disassembled and illustrated. Each part is given the next available number as its symbol name in the library as shown in Figure.

Originally, the CADD drawings were combined with text (written using Microsoft Word) in desktop-publishing software to create technical publications. Now, the CADD drawings are added to document ﬁles in specialized technical-publishing software. The entire parts library is available to both CADD and technical-publication software users (see Figure).

From the point of view of cost management, the parts library has saved hundreds of hours of work. From the illustrator’s view, the parts library helps improve productivity and frees time for new or complex projects.

### Design Reusability In Solidworks

“I know that part’s here somewhere… I think I saved it in the XXX project folder…  We designed a similar assembly last year…” Sound familiar? If you’ve ever spent time hunting for previous designs or recreated the same content multiple times, you’re not alone. Fortunately, SOLIDWORKS includes powerful capabilities that minimize this pain and help you get your job done fast.

### Design Library

• Includes out of the box standard mechanical design content (like o-ring grooves, keyways, sheet metal punches, etc.)
• Windows folder structure – easy to organize and share with co-workers
• Easily add content you re-use (like drawing notes, feature sets, purchased parts and assemblies, company logos, welding symbols, start parts, and much more)

### SOLIDWORKS Toolbox

• Included with SOLIDWORKS professional and premium (turn on the add-in)
• Thousands of standard hardware components (o-rings, nuts, bolts, washers, gears, retaining rings, bearings, pins, and much more)
• Fully configured with all standard sizes and lengths
• Autosize to your corresponding features
• Can add BOM details and custom components using the “Configure Toolbox” wizard

### Integrated SOLIDWORKS Search

• Setup all locations you want to index
• Tools > Options > System Options > File Locations > Search Paths
• Set options like when to index and whether to show 3DCC results
• Tools > Options > System Options > Search
• Use the keyboard shortcut “I” to activate the search

### 3D Content Central

• Free online resource
• Thousands of vendors with configurable and downloadable 3D files and tons of user-uploaded content too
• Preview 3D files right in the browser
• Use integrated SOLIDWORKS search (if 3DCC set to show in results)
• Drop right into SOLIDWORKS

### Mate References

• Add to any part or assembly you will re-use and want to snap into position
• Use a circular edge between a cylindrical and planar face to get both concentric and coincident mates added.
• Add up to 3 references and name the mate reference to get it to find mating components automatically. Just use the same name for the mate reference in the mating part.  Put into an assembly and they will snap together like magic.

### Smart Components

• Allow you to insert features, parts, or both. Think mounting holes and hardware for example.
• Features can include full tolerances that will carry over.
• Use a simple setup assembly when creating the smart component (I store them in my design library).
• Create: edit the part in the context of the setup assembly and use Tools > Make Smart Component.
• Use: insert and position the part in your assembly. Click the smart component icon in the graphics or right-click the part > Insert Smart Features.  Select what to include and any references needed.

# WHAT IS DRAFTING STANDARDS

## DRAFTING STANDARDS

Most industries, schools, and companies establish standards, which are guidelines that specify drawing requirements, appearance, and techniques, operating procedures, and record-keeping methods. The Australian Standards deﬁnes the term standard as a set of technical deﬁnitions and guidelines, how-to instructions for designers, manufacturers, and users. Standards promote safety, reliability, productivity, and efﬁciency in almost every industry that relies on engineered components or equipment. Standards can be as short as a few paragraphs or hundreds of pages long, but experts write them with knowledge and expertise in a particular ﬁeld who sit on many committees. The Australian Standards deﬁnes the term code as a standard that one or more governmental bodies adapt and has the force of law. Standards are considered voluntary because they serve as guidelines. Standards become mandatory when a business contract or regulations incorporate them.

Standards are important for engineering communication because they serve as a common language, deﬁning quality and establishing safety criteria. Costs are lower, and training is simpliﬁed when procedures are standardized. Interchangeability is another reason for standardization, so a part manufactured in one location ﬁts with a mating part manufactured in another location.

Drawing standards apply to most settings and procedures, including:

• CADD ﬁle storage, naming, and
• File templates, which are ﬁles that contain standard ﬁle settings and objects for use in new ﬁles.
• Units of
• Layout
• Borders and title
• Symbols
• Layers, and text, table, dimension, and another drafting
• Plot styles and plotting

Company or school drawing standards should follow appropriate national industry standards. Though standards vary in content, the most important aspect is that standards exist and are understood and used by all design and drafting personnel. When you follow drawing standards, drawings are consistent, you become more productive, and the classroom or ofﬁce functions more efﬁciently.

### Australian Drafting Standards

The standards Australia is a professional engineering organization for mechanical engineering. The standards Australia publishes standards documents sponsors technical conferences and educational programs and conducts professional development courses. The standards Australia is an accredited standard developing organization that meets the requirements of various codes.

The standards Australia publishes standards for numerous disciplines. Most standards Australia standards that focus on speciﬁc areas of engineering drawing and related practices receive the designation.

### ISO Drafting Standards

The ISO is an international organization that currently includes members from 163 countries. Australia is a member. The ISO provides an extensive list of drafting standards and related documents. The ISO 2768 standard, General Tolerances, details speciﬁc ISO dimensioning and tolerancing practices. This standard is particularly important when preparing a metric drawing according to Australian standards because the ISO normally controls metric tolerancing. A general note that states the ISO 2768 class for general tolerances, such as ISO 2768-m, shall be placed on the drawing. For more information or to order standards, go to the ISO Web site at www.iso.org.

### CADD Skill Standards

The Computer-Aided Drafting and Design (CADD) skill standards, developed in cooperation with the National occupational skill standards, summarizes CADD occupation skills generic to all CADD disciplines, software, and entry-level.

## AS 1100

AS 1100 is an Australian Standard for technical drawing including both mechanical and architectural designs. AS 1100 standard drawings contain attributes that are universal around Australia. Standards Australia publishes the standard.

The standard consists of six parts,

• Part 101: General principles (1992)
• Part 201: Mechanical engineering drawing (1992)
• Part 301: Architectural drawing (2008)
• Part 401: Engineering survey and engineering survey design drawing (1984)
• Part 501: Structural engineering drawing (2002)

You cannot view these without purchasing a licence first.

### A

A – Ampere
A/C – Air Conditioning
A/H – After Hours
AB – As-Built
ABBR – Abbreviation
ABS – Absolute
AEC – Architecture, Engineering, and Construction
AF – Across Flats
AFL – Above Floor Level
AFL – Above Finished Level
AG – Agricultural pipe drain
AGL – Above Ground Level
AHD – Australian Height Datum
AHU – Air Handler Unit
APPROX – Approximately or Approximate
ARRGT – Arrangement
AS – Australian Standard
ASCII – American Standard Code for Information Interchange
ASSD – Assumed Datum
ASSY – Assembly
ATF – Along Top Flange
AUTO – Automatic
AUX – Auxillary
AVG – Average

### B

B – Basin or Bottom
BLDG – Building
BNS – Business Network Services
BOT – Bottom
BQ – Bendable Quality
BRG – Bearing
BRS – Brass
BSP – British Standard Pipe
BT – Bath Tub
BT – Boundary Trap
BTM – Bottom
BW – Both Ways

### C

C – C shaped steel purlin
C/C – Cross Centres
CAD – Computer-Aided Design.
Less commonly use is Computer Assisted Drafting.
CAM – Computer Aided Manufacture
CAP – Capacity
CBORE – Counterbore
CCTV – Closed Circuit Television
CFW – Continuous Fillet Weld
CHAM – Chamfer
CHCL – Channel
CH HD – Cheese Head
CHS – Circular Hollow Section
CI – Cast Iron
CIRC – Circumference or Circle
C.J. OR CJ – Control Joint (or Construction Joint)
CL – Center Line
CLG – Control Joint
CLR – Clearance
CMU – Cement Masonry Unit
CNC – Computer Numerical Control
CNR – Corner
CNJ – Construction Joint
COEF – Coefficient
COL – Column
COMMS – Communications
CONC – Concentric
CONN – Connection
CONT – Continuous
CP – Chrome Plated
C REC HD – Cross-Recess Head
CRS – Colled Rolled Steel
CTRS – Centres
CS – Cleaners Sink
CS – Cast Steel
CKS – Countersink
CSK HD – Countersunk Head
CT – Controller
CTR – Contour
CTR(S) – Centre/S
CTRL – Control
CTRS – Centers
CU – Dental Cuspidor
CUP HD – Cup Head
CVR – Cover
CYL – Cylinder
°C – Degrees Celsius

### D

DAR – Dressed All Round
DD – Design Drawing
DED – Dedendum
DET – Detail
DIA – Diameter
DIAG – Diagram
DIAG – Diagonal
DICL – Ductile Iron Cement Lined (pipe)
DIST – Distance
DIM – Dimension
DN – Diameter Nominal
DP – Down Pipe
DP – Diametral Pitch
DR – Dryer
DRG – Drawing
DW – Dishwasher
DWG – Drawing
DWG(S) – Drawing/S

### E

E – Modulus of Elasticity
EA – Equal Angle (steel)
EF – Each Face
E.J. or EJ – Expansion Joint
EL – Elevated Level
EL – Elevation
ELEC – Electrical
ELEV – Elevation
EQ – Equal
EQUIP – Equipment
EQUIV – Equivalent
EW – Each Way
EWB – Electric Water Boiler
EWC – Electric Water Cooler
EXT – External

### F

FB – Footing Beam
F’c – Characteristic Concrete Strength
FCU – Fan Coil Unit
FFL – Finished Floor Level
FHR – Fire Hose Reel
FIQ – Figure
FILL HD – Fillister Head
FL – Floor Level
FL – Flat or Flat Plate
FLG – Flange
FOC – Fibre Optic Cable
FS – Far Side
FSBL – Full Strength Butt Weld
FTG – Footing
FTP – Fibre Termination Panel (fibre optical cable)
FW – Fillet Weld
FWF – From Web Face (steel)

### G

GA – General Arrangement
GALV – Galvanized
GCI – Galvanized corrugated iron.
GD – Grid
GI – Galvanized Iron
GIP – Galvanized Iron Pipe
GIS – Graphic Information System
GPO – General Purpose Outlet
GRF – Geometric Reference Frame
GSM – Global System of Moblie or “Groupe Speciale Mobile” in French

### H

H – Prewash Hose Reel
HEX HD – Hexagon Head
HEX SOC HD – Hexagon Socket Head
HOR – Horizontal
HORIZ – Horizontal
HP – High Pressure
HRA – Rockwell Hardness A
HRB – Rockwell Hardness B
HRC – Rockwell Hardness C
HS – High Strength
HT – Height
HTS – High-Tensile Steel
HV – Diamond Pyramid Hardness Number (Vickers)
HWB – Hair Wash Basin

### I

I – Moment of Inertia
ID – Inside Diameter
IE – Invert Elevation
I.J. or IJ – Isolation Joint
IL – Invert Level
INT – Internal
IO – Inspection Opening
IP – Intersection Point
ISO – International Standard Organisation

### J

JIS – Japanese Industry Standard
JT – Joint
JUNC – Junction

### K

kHz – Kilohertz
K.J. or KJ – Key Joint
KS – Kitchen Sink
KWh – Kilo Watt Hour (metre)

### L

L – Steel Angle
LAN – Local Area Network
LG – Length
LGX – Line Group Cross (Connector, fibre optical cable)
LH – Left Hand
LMC – Least Material Condition
LONG – Longitudinal
LPG – Liquid Petroleum Gas
LT – Laundry Trough

### M

m – Metres (English) or Meters
MATL – Material
MAX – Maximum
M/C – Machine
MDF – Main Distribution Frame (Telecommunications)
MFR – Manufacturer
MHz – Megahertz
Mickey Mouse – A toy project, of very low quality.
MI – Malleable Iron
MIN – Minimum
MISC – Miscellaneous
M.J. or MJ – Movement Joint
mm – Millimetres
MMC – Maximum Material Condition
MOD – Modification
MS – Mild Steel
MTG – Mounting
MUSH HD – Mushroom Head

### N

NC – Normally Closed
NEG – Negative
NET – Network
No. – Number
NOM – Nominal
NS – Near Side
NS – Nominal Size
N.S.O.P. – Not Shown On Plan
NTS – Not To Scale
NZS – New Zealand Standard

### O

OA or O/A – Overall
OCT – Octagon
OD – Outside Diameter
OPT – Optional

### P

P – Pipe
PA – Pressure Angle
PAR – Parallel
PATT – Pattern
PCD – Pitch Circle Diameter
PFC – Parallel Flange Channel
PL – Plate
PL – Pipeline
POS – Positive
POSN – Position
PREFAB – Prefabricated
PT – Pressure Tapping
PT – Part
PVC – Poly Vinyl Chloride
uPVC – UV Stabilized Poly Vinyl Chloride

QTY – Quantity

### R

Ra – Roughness Value
RD – Round
REF – Reference
RECT – Rectangular
REINF – Reinforcement
REQ’D or REQD – Required
REV – Revision
RH – Right Hand
RHS – Rectangular Hollow Section (rarely Rolled Holled Section)
RL – Reduced Level or Relative Level
RO – Reverse Osmosis (water treatment)
RSA – Rolled Steel Angle
RSC – Rolled Steel Channel
RSD CSK HD – Raised Countersunk Head
RSJ – Rolled Steel Joist

### S

S – Snug fit or tightened (bolts)
S – Sink
SAN – Sanitary
SDU – Sanitary Disposal Unit
SECT – Section
SF – Strip Footing
SF – Spot Face
SFL – Structural Finished Level
SH – Sheet
SHR – Shower
SHS – Square Hollow Section
SIM – Similar
SK – Sketch
SL – Structural Level
SPT – Spigot
SQ – Square
SS or S/S – Stainless Steel
SSL – Structural Slab Level
ST – Steel
STD – Standard
SW – Switch

### T

T – Top
TB – Tie Beam
TB – Fully tensioned, bearing type (bolts)
TEMP – Temperature
TF – Fully tensioned, friction type (bolts)
TFC – Taper Flange Channel
THK – Thick
TO or T.O. or T.OFF – Top Off
TOL – Tolerance
TP – Tangent Point
TP – True Position
TP – True Profile
TR – Laundry Trough
TUN – Tundish
TYP – Typical

### U

U/S – Under Side
UA – Unequal Angle (steel)
UB – Universal Beam (steel)
UC – Universal Column (steel)
UCUT – Undercut
UNO – Unless Noted Otherwise (UON is prefered)
UON – Unless Otherwise Noted
uPVC – Unplasticized Polyvinyl Chloride
UR – Urinal

VER – Vertical
VERT – Vertical
VOL – Volume

### W

WAN – Wide Area Network
WB – Welded Beam (steel)
WC – Welded Column (steel)
WC – Water Closet (toilet).
Where the poo and wee goes.
WC(P) – Water Closet With ‘P’ Trap
WC(S) – Water Closet With ‘S’ Trap
WD – Working Drawing
WM – Washing Machine
WP – Water Proof or Work Point
WI – Wrought Iron

### X

X – By. Example, “N12 x 1200 long” also means “N12 by 1200 long”.

YP – Yield Point

### Z

Z – Zulu (Greenwich Mean Time)
Z – Z shaped steel purlin
Z – Modulus of Section

### Other Characters

°C – Degrees Celsius
Ø – Diameter
# – Number
/tb – Fully tensioned, bearing type (bolts)
/tf – Fully tensioned, friction type (bolts)
/s – Snug fit or tightened (b

# Intellectual Property Rights and Patent Application

### Intellectual Property Rights

The success of a company often relies on the integrity of its employees. Products are normally the result of years of research, engineering, and development. This is referred to as the intellectual property of the company. Protection of intellectual property can be critical to the success of the company in a competitive industrial economy. This is why it is very important for employees to help protect design ideas and trade secrets. Many companies manufacture their products in strict, secure, and secret environments. You will often ﬁnd proprietary notes on drawings that inform employees and communicate to the outside world that the information contained in the drawing is the property of the company and is not for use by others.

### Software Piracy

Software piracy is the unauthorized copying of software. Most software licenses support use at one computer site or by one user at any time. When you buy software, you become a licensed user. You do not own the software. You are allowed to make copies of the program for backup purposes, but it is against the law to give copies to colleagues and friends. Software companies spend a lot of money creating software programs for your professional and personal applications. Each new release usually provides you with improved features and more efﬁcient use. When you use software illegally, you hurt everyone by forcing software companies to charge more for their products. Ethically and professionally, use software legally and report illegal use when observed.

A copyright is the legal rights given to authors of original works of authorship. The Australian Constitution establishes copyright and patent law and empowers the federal government to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries. Copyrights control exclusively the reproduction and distribution of the work by others. In Australia, published or unpublished works that are typically copyrightable include:

• Literary works, including computer programs and
• Musical works, including any accompanying
• Dramatic works, including any accompanying
• Pantomimes and choreographic
• Pictorial, graphic, and sculptural
• Motion pictures and other audiovisual
• Sound
• Architectural works and certain other intellectual

Copyright protection exists from the time the work is created in ﬁxed form. The fixed form may not be directly observable; it can be communicated with the aid of a machine or device. The copyright in the work of authorship immediately becomes the property of the author who created the work. Copyright is secured automatically when the work is created, and the work is created when it is ﬁxed in a copy or phono- recorded for the ﬁrst time. Copies are material objects from which the work can be read or visually perceived directly or with the aid of a machine or device. A copyright notice can be placed on visually perceptible copies. The copyright notice should have the word Copyright, the abbreviation Copr., or the symbol © (or ® for phonorecords of sound recordings); the year of ﬁrst publication; and the name of the owner of the copyright.

### Patents

A patent for an invention is the grant of a property right to the inventor, issued by the IP AUSTRALIA. The term of a new patent is 20 years from the date on which the application for the patent was ﬁled in Australia or, in special cases, from the date an earlier related application was ﬁled, subject to the payment of maintenance fees. The IP AUSTRALIA patent grants are effective only within Australia. The patent law states, in part, that any person who "invents or discovers any new and useful process, the machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent," subject to the conditions and requirements of the law.

The patent law speciﬁes that the subject matter must be "useful." The term useful refers to the condition that the subject matter has a useful purpose and must operate. You cannot patent laws of nature, physical phenomena, and abstract ideas. A complete description of the actual machine or other subject-matter is required to obtain a patent.

### Application for a Patent

The IP AUSTRALIA offers standard and innovation patent applications. A standard patent application is for the full patent, which lasts 20 years. The innovation patent application is for a temporary patent that lasts for one year.

##### Standard Application for a Patent

According to the IP AUSTRALIA, a standard application for a patent is made to the assistant commissioner for patents and includes:

1. a written document that has a speciﬁcation and an oath or declaration,
2. a drawing in those cases in which a drawing is necessary, and
3. the ﬁling fee.

All application papers must be in the English language, or a translation into the English language is required. All application papers must be legibly written on only one side by either a typewriter or mechanical printer in a permanent dark ink or its equivalent in portrait orientation on ﬂexible, strong, smooth, nonshiny, durable, white paper. Present the papers in a form having sufﬁcient clarity and contrast between the paper and the writing to permit electronic reproduction. The application papers must all be the same size, either 21.0 cm by 29.7 cm (DIN size A4) or 21.6 cm by 27.9 cm (81¤2 3 11 in.). Application documents must have a top margin of at least 2.0 cm (3⁄4 in.), a left-side margin of at least 2.5 cm (1 in.), a right- side margin of at least 2.0 cm (3⁄4 in.), and a bottom margin of at least 2.0 cm (3⁄4 in.), with no holes made in the submit- ted papers. It is also required that the spacing on all papers be 11¤2 or double spaced, and the application papers must be numbered consecutively, centrally located above or below the text, starting with page 1. All required parts of the application must be complete before sending the application, and it is best to send all of the elements together. The IP AUSTRALIA numbers all applications received in serial order and the applicant will be informed of the application serial number and ﬁling date by a ﬁling receipt.

##### Innovation Application for a Patent

If you want protection for an invention with a short market life that might be superseded by newer innovations, such as computer-based inventions, an innovation patent is worth considering.

An innovation patent lasts up to eight years and is designed to protect inventions that do not meet the inventive threshold required for standard patents. It is a relatively quick and inexpensive way to obtain protection for your new device, substance, method or process.

The innovation patent requires an innovative step rather than an inventive step. An innovative step exists when the invention is different from what is known before, and the difference makes a substantial contribution to the working of the invention. The innovation patent protects an incremental advance on existing technology rather than being a groundbreaking invention.

An innovation patent is usually granted within a month of filing the complete application. This is because there is no examination before it is granted.

An innovation patent is only legally enforceable if it has been examined by us and found to meet the requirements of the Patents Act 1990, and has been certified. Examination of an innovation patent will only occur if requested by the patentee, a third party or if the Commissioner of Patents decides to examine the patent. The patentee will not be required to pay for examination until it is requested.

##### Phase-out of the innovation patent

The Australian Government has begun the process of phasing out the innovation patent with the passing of legislative amendments. This means:

• The last day you can file a new innovation patent will be 25 August 2021.
• Existing innovation patents that were filed on or before 25 August 2021 will continue in force until their expiry. This will ensure current rights holders are not disadvantaged.

The Government remains committed to dedicated support services to help small and medium enterprises (SMEs) navigate the intellectual property (IP) system. Australian SMEs will receive further dedicated support, with an SME case management service, the SME fast track service, a dedicated outreach program and online portal, to be launched as the innovation patent is phased out over the next 18 months.

### The quick guide to innovation versus standard patents

Innovation patent Standard patent
Your invention must: Be new, useful and involve an innovative step. Be new, useful and involve an inventive step.
The application should include: A title, description, up to five claims, drawings (if applicable), an abstract and forms. A title, description, any number of claims, drawings (if applicable), an abstract and forms.
A patent is granted if: The application satisfies formality requirements (note: a 'granted' innovation patent cannot be enforced unless examined). The application is examined and found to satisfy the relevant requirements of the Patents Act 1990.
Examination: Optional. The examination can be requested by you or anyone else. Mandatory. The relevant requirements of the Patents Act 1990 must be met before a patent is granted. Can only be requested by the applicant.
Certification: Is given if the innovation patent complies with the relevant requirements of the Patents Act 1990 in the examination. Only after certification can the patent be enforced. N/A
Publication in the Australian Official Journal of Patents: At grant and again at certification. Eighteen months from earliest priority date and again at acceptance.
Protection period: Up to eight years if annual fees are paid. Up to 20 years if annual fees are paid (or up to 25 years for pharmaceuticals).
How long does the process take? Approximately one month for the grant. Six months for examination if you make a request. Six months to several years depending on circumstances.

### Patent Drawings

There is no requirement for a specific number of views. However, you must provide sufficient views to fully display your design, which usually requires a number of views.
We prefer traditional views (front, side and top) but will also accept perspective or isometric views. (See image).

All views must show exactly the same design. This particularly applies to colour, as colour is usually a visual feature of the design.

#### Key points for drawings

Drawings should:

• be accurately drawn, not sketches, with well-defined line-work
• only show the design in question and no descriptive wording or dimensions. However, labelling of views such as 'perspective view' or 'rear views' is acceptable
• on A4 size paper if lodged by post
• use broken or dashed lines when highlighting:
• elements of the product other than those bearing the visual features of the design
• parts of the design that are referred to in the statement of newness and distinctiveness
• boundaries, such as a pattern applied to part of a surface, stitching and perforations
• features that establish an environmental context.

Shading and cross-hatching can be used to show a visual feature of the design.

#### Key points for photographs or digital images

Photographs or digital images should:

• be clear originals
• show the product against a plain contrasting background and avoid matter not relevant to the design
• be A4 or mounted on A4 white paper if lodged by post.

#### Other details

If it's a multiple design application, then each design should be clearly indicated, with each design shown on a separate sheet.

#### Complex products

Sometimes a design is applied to a part of a complex product, and that part can be readily assembled and disassembled from that product. If the component part qualifies as a product, then broader protection may be gained by defining this as a stand-alone part.

According to the IP AUSTRALIA publication Basic Facts About Registering a Trademark, a trademark is a word, phrase, symbol or design, or combination of words, phrases, symbols, or designs that identiﬁes and distinguishes the source of the goods or services of one party from those of others. A service mark is the same as a trademark except that it identiﬁes and distinguishes the source of a service rather than a product. Normally, a mark for goods appears on the product or on its packaging, whereas a service mark appears in advertising for services. A trademark is different from a copyright or a patent. As previously explained, a copyright protects an original artistic or literary work, and a patent protects an invention.

Trademark rights start from the actual use of the mark or the ﬁling of a proper application to register a mark in the AUSTRALIA stating that the applicant has a genuine intention to use the mark in commerce regulated by the AUSTRALIA. Federal registration is not required to establish rights in a mark, nor is it required to begin use of a mark. However, federal registration can secure beneﬁts beyond the rights acquired by just using a mark. For example, the owner of a federal registration is presumed to be the owner of the mark for the goods and services speciﬁed in the registration and to be entitled to use the mark nationwide. Generally, the ﬁrst party who either uses a mark in commerce or ﬁles an application in the AUSTRALIA has the ultimate right to register that mark. The authority of the AUSTRALIA is limited to determining the right to register. The right to use a mark can be more complicated to determine, particularly when two parties have begun use of the same or similar marks without knowledge of one another and neither has a federal registration. Only a court can make a decision about the right to use. Federal registration can provide signiﬁcant advantages to a party involved in a court proceeding. The AUSTRALIA cannot provide advice concerning rights in a mark. Only a private attorney can provide such advice.

Trademark rights can last indeﬁnitely if the owner continues to use the mark to identify its goods or services. The term of federal trademark registration is ten years, with ten-year renewal terms. However, between the ﬁfth and sixth year after the date of initial registration, the registrant must ﬁle an ofﬁcial paper giving certain information to keep the registration alive. The registration is cancelled if this is not done. Please conﬁrm speciﬁc trademark details and requirements with the AUSTRALIA.

# WHAT IS THE HISTORY OF ENGINEERING DRAWING

Individuals with talent, wisdom, vision, and innovative ideas have inﬂuenced the history of engineering drawing. Major changes in agriculture, manufacturing, mining, and transport also greatly inﬂuenced the evolution of engineering drawing and had an overpowering effect on socioeconomic and cultural conditions between the eighteenth and nineteenth centuries. Recently and more rapidly, computers have become a driving force in the way people create engineering drawings.

Early Drawing Practices

prehistoric humans created images on cave walls and rocks as a form of communication for hunting and gathering societies, to provide ritual or spiritual meaning, and for decoration.

Prehistoric drawings and paintings, known as pictograms, and carvings, known as petroglyphs, show a variety of animals and human shapes. Pictograms and petroglyphs are not engineering drawings, but they do represent early graphic forms of communication. For thousands of years, designers of ancient structures and machines used sketches, drawings, and documents to represent inventions and architecture and help design and distribute information to workers. However, activities such as farming, craft making, and toolmaking, and construction generally followed established standards of the time without the use of formal drawings as a guide. Production was more like a form of art than engineering, and each item was unique.
Early engineering drawings representing machines and buildings appear in the fourteenth and ﬁfteenth centuries. These drawings were generally in the form of pictorial sketches with written descriptions that helped workers understand the intent of the drawings for fabrication or building. Early engineering drawings served as a reference for craft workers to construct a building or manufacture a product. Craft workers viewed the drawings and written descriptions and made interpretations based on their own experience and knowledge of current standard practices. Speciﬁc dimensions were not necessary, because each building or machine was different. Early engineering drawings were also an art form used during presentations to the persons who requested the designs.

Engineering Drawing Pioneers

Most early creators of engineering drawings were artists and inventors. Some of the best-known early engineering drawings are the work of Italian Leonardo da Vinci. Leonardo is well known for his art, such as The Last Supper in 1498 and the Mona Lisa in 1507. He was also an inventor who designed machines such as the glider shown in Figure and military equipment such as the giant crossbow. Leonardo’s drawings were those of an artist and were not in the form of engineering drawings. Leonardo’s drawings were pictorial and generally without dimensions. No multiview drawings of Leonardo’s designs are known to exist. Multiview drawings are 2-D drawings of objects organized in views.
Skilled tradespeople worked from the pictorial sketches and representations to construct models of many of Leonardo’s designs. Each machine or device was unique, and parts were not interchangeable. Leonardo was also an early mapmaker. In 1502, Leonardo created a map containing the town plan of Imola, Italy. Authorities commissioned Leonardo as the chief military engineer and architect because of this mapmaking. Arguably, this early work was more artistic than the beginning of engineering drawing, but this work holds a special place in history.
Approximately the same time as Leonardo da Vinci created his drawings, awareness developed that drawings require greater accuracy and dimensions. An early author of architecture and engineering was an Italian man, Leon Battista Alberti. Leon’s writing covered a wide range of subjects, from architecture to town planning and from engineering to the philosophy of beauty. In 1435 and 1436, Leon also wrote two works that explored the need to incorporate more geometry in drawings. Leon also proposed drawings with multiple views rather than the commonly used pictorial drawings.
The importance of using multiview two-dimension drawings was also inﬂuenced by the development of descriptive geometry in the work of French philosopher and mathematician René Descartes (1596–1650) and the work of Frenchman Gaspard Monge (1746–1818). René was the inventor of the Cartesian coordinate system, and he founded analytic geometry, the link between algebra and geometry. The Cartesian coordinate system uses numerical coordinates to locate points in space according to distances measured in the same unit of length from three intersecting axes. The Cartesian coordinate system is the basis for establishing points when using CADD today.
Gaspard Monge created a large-scale plan of a town using his own methods of observation and instruments that he designed. As a result, authorities commissioned Gaspard as a drafter and pupil in the practical school of the military institution. Given a project to design a proposed fortress, Gaspard used his geometrical method to create the design quickly. Continuing his research, Gaspard arrived at a graphic method of the application of geometry to construction, now called descriptive geometry. Descriptive geometry is the system of graphic geometry that uses plane projections to describe and analyze their properties for engineering drafting applications.

Many early drafters had degrees in engineering and began to realize the importance of creating accurate and detailed engineering drawings. However, much of the drafting was in the form of line drawings, with watercolour paints used to high-light the drawings as shown in the architectural elevation of a home. Drawing continued to be basic line drawings with little dimensioning practice. An example is the early architectural ﬂoor plans shown in Figure used to construct a home. Craft workers also followed architectural details such as the gable design shown in Figure. There were few if any dimensions and standards, so each building was similar but different. This practice lasted until the early part of the twentieth century.

Into the late 1800s and early 1900s, inventors, engineers, and builders worked on each product on a one-of-a-kind basis. Manufactures produced parts from hand sketches or hand drawings on blackboards. American engineer and inventor Coleman Sellers, in the manufacture of ﬁre engines, had blackboards with full-size drawings of parts. Blacksmiths formed parts and compared them to the shapes on the blackboards. Coleman Sellers son, George Sellers, recalls lying on his belly using his arms as a radius for curves as his father stood over him direct-ing changes in the sketches until the drawings were satisfactory. Most designs used through the 1800s began as a hand sketches of the objects to be built. Workers then converted the sketches into wooden models from which patterns were constructed. Some companies followed this practice well into the twentieth century. An example is Henry Ford and his famous blackboards. What was new, though, was that the blackboards were also the Henry Ford drafting tables. Henry would sketch cars and parts three-dimensionally and have pattern makers construct full-size wooden models.

### The Inﬂuence of Interchangeability

The Industrial Revolution was a period from the eighteenth to nineteenth centuries when major changes took place in agriculture, manufacturing, mining, and transport. The need for interchangeability in manufactured products became important during the Industrial Revolution. Interchangeability refers to parts manufactured identically within given tolerances. interchangeable parts are produced to speciﬁcations that make sure they are so nearly identical that they ﬁt into any product for which they are designed. One part can replace another of the same part without custom ﬁtting. Interchangeability allows easy assembly of new products and easier repair of exist- ing products while minimizing the time and skill required for assembly and repair.

The application of interchangeability started with the ﬁrearms industry. Before the eighteenth century, gunsmiths made guns one at a time, and each gun was unique. If one component of a ﬁrearm needed to be replaced, the entire weapon was sent back to the gunsmith for custom repairs or the ﬁrearm was discarded. The idea of replacing these methods with a system of interchangeable manufacture gradually developed during the eighteenth century. Interchangeability was not realized except in special examples until the development of the micrometre in the late 1800s; even then, interchangeability was not easy to achieve. Without the concept of interchangeability, accurate drawings were not necessary. After these advances, engineering drawing began to evolve more rapidly in the nineteenth century.

### Drafting Practices and Equipment

Early engineering drawings were often works of art and commonly made with ink. Drafters initially drew using a pencil, T-square, triangles, scales, irregular (French) curves, and drawing instruments such as compasses and dividers. Drafting textbooks as late as the fourth edition of this textbook spent pages describing how to sharpen, hold, and properly use pencils to draw quality uniform lines. Drafters often traced original pencil drawings onto cloth using pen and ink. Drafters always paid skilled attention to lettering quality on drawings. Engineering drafters would use a speciﬁc lettering style referred to as vertical uppercase Gothic. Architectural drafters used a more artistic style of lettering that deﬁned their drawings as uniquely related to their discipline. Over the years, various templates and other devices were introduced that allowed drafters to produce consistent quality lettering, although most professional drafters preferred to make quality freehand lettering.

Drafters initially created drawings by hand on a drafting table referred to as aboard. An advance in drafting occurred with the introduction of the drafting machine, which replaced the T-square, triangles, scales and protractor for creating drawings. The drafting machine mounts to the table or board and has scales attached to an adjustable head that rotates for drawing angles. When locked in a zero position, the scales allow drawing horizontal and vertical lines and perpendicular lines at any angle orientation. There are arm and track drafting machines. The arm machine has arms attached to a mounting bracket at the top of the table. The arms control the movement of the head. The track machine has a traversing track that mounts to the table and a vertical track that moves along the horizontal track. The machine head traverses vertically on the track as shown in Figure.

Many architectural drafters used a device called a parallel bar, is a long horizontal drafting edge attached to each side of the table that moves up and down on the table. The parallel bar allows the drafter to draw horizontal lines, and triangles are used on the bar to draw angled lines. During the decades after World War II, drafting equipment suppliers introduced a variety of materials to improve the productivity of the drafting process.

### Drawing Reproduction

About the same time as interchangeability became important and engineering drawings were evolving, preserving, and duplicating original drawings became important. There was a need to reproduce drawings easily for distribution to manufacturers or builders, so the blueprint process developed. A blueprint is a contact chemical-printing process of a drawing or other image copied on paper with white lines on a blue background. As drawing reproduction evolved, a diazo process that created blue line copies with a white background replaced the blueprint process. Until recently, all drawing reproductions were commonly referred to as blueprints. Today, ofﬁces use printers, plotters, and engineering copiers that use xerography to reproduce CADD drawings. The generic term print has replaced the term blueprint.

### Computer-Aided Design and Drafting

During the 1980s and 1990s, CADD rapidly became a technology to take seriously. Companies began considering the power of CADD as computer systems and CADD software developed capabilities and features that made them useful in producing professional drawings. Drafters who had used manual drafting for their entire careers had to face the challenge of converting their artistic skill into drawings created using a computer. This was a difﬁcult challenge for many drafters. Soon schools began teaching drafting technology using CADD. This gave the traditional manual drafters an opportunity to learn the new technology and for new trainees to develop CADD knowledge and skills at the entry-level.