Section 1 Introduction to Drafting Chapter 3 Introduction to CAD Section 1 Introduction to Drafting

Objectives Explain computer-aided drafting and design. Identify common applications for CAD in different areas of drafting. List the components of a typical CAD workstation. Identify features of CAD software and how they should be evaluated when selecting a program. Explain the advantages of specific CAD applications. © Goodheart-Willcox Co., Inc.

What Is CAD? Tool used to plan and design parts. Automates symbol creation and object duplication. Incorporates hardware and software. Requires knowledge of drafting principles and practices. © Goodheart-Willcox Co., Inc.

Why Use CAD? Productivity Flexibility Uniformity Ease of scaling (EdgeCAM/Pathtrace) © Goodheart-Willcox Co., Inc.

CAD Productivity Benefits Significant time and money savings over manual drafting. Increased drawing quality. Reduced number of revisions. Symbol library applications. Schedule generation and analysis tools. © Goodheart-Willcox Co., Inc.

Symbol Library © Goodheart-Willcox Co., Inc.

CAD Flexibility Benefits Plotting at a variety of scales. Presentation and media options. Data sharing. © Goodheart-Willcox Co., Inc.

CAD Uniformity Benefits Accurate adherence to standards. Consistent symbol generation. Ensured line quality. © Goodheart-Willcox Co., Inc.

CAD Scaling Benefits Objects typically drawn at full size. Drawing plotted at specified scale. Drafting time and potential for errors minimized. © Goodheart-Willcox Co., Inc.

Mechanical CAD Applications Automatic schedule generation. Rendering capability. Animation functions. © Goodheart-Willcox Co., Inc.

Part Schedule Production © Goodheart-Willcox Co., Inc.

CAD Workstation Used together with CAD software. Often connected to other devices in network. May be connected to mainframe. © Goodheart-Willcox Co., Inc.

CAD Workstation (Cont.) © Goodheart-Willcox Co., Inc.

Computer Components Central processing unit (CPU) Output device Input device Storage devices © Goodheart-Willcox Co., Inc.

Storage Devices Used to save data for later use. Computer hard drive CD-R drive CD-RW drive DVD drive © Goodheart-Willcox Co., Inc.

Display Device Typically a CRT or LCD monitor. Size defines screen area. Video card should meet needs of application. © Goodheart-Willcox Co., Inc.

Input Devices Keyboard Mouse Trackball Digitizer puck Light pens © Goodheart-Willcox Co., Inc.

Output Devices Pen plotter Laser printer Inkjet printers Inkjet plotters © Goodheart-Willcox Co., Inc.

Pen Plotter Traditional device for CAD work. Generates vector drawings. Used for large-format output. Produces very accurate line quality. Disadvantage is slow operation. © Goodheart-Willcox Co., Inc.

Inkjet Printers and Plotters Generate raster drawings. Used for high-quality color renderings. Potential disadvantages are slow operation and cost. (DesignJet Division, Hewlett-Packard) © Goodheart-Willcox Co., Inc.

CAD Packages Types and costs vary based on features provided. Lower-end systems used for 2D drawing. More advanced software available for 3D work. © Goodheart-Willcox Co., Inc.

Selecting a CAD Package Consider product features and specific needs. Ease of use Hardware requirements Product support Warranty coverage Specific tools in software Cost © Goodheart-Willcox Co., Inc.

Types of CAD Packages General purpose CAD packages Advanced mechanical drafting and modeling CAD packages AEC CAD packages © Goodheart-Willcox Co., Inc.

General Purpose CAD Features Functions for drawing objects Automated dimensioning Hatch pattern generation Text functions and font types Editing functions © Goodheart-Willcox Co., Inc.

CAD Hatch Patterns © Goodheart-Willcox Co., Inc.

General Purpose CAD Features Layers Object display colors Linetype definitions Coordinate entry methods Methods for entering commands © Goodheart-Willcox Co., Inc.

General Purpose CAD Features (Cont.) Drawing unit formats Display controls Drawing aids Printing or plotting functions Customization options Data exchange methods © Goodheart-Willcox Co., Inc.

3D Drawing Features Available in more advanced programs. Shading and rendering Animation Mass property analysis © Goodheart-Willcox Co., Inc.

Types of 3D Models Surface model Solid model © Goodheart-Willcox Co., Inc.

Advanced Mechanical Drafting and Modeling CAD Packages Designed for advanced engineering applications. Provide additional 3D modeling features. Commonly used in automated manufacturing. © Goodheart-Willcox Co., Inc.

Advanced Mechanical Drafting and Modeling Features Solid modeling tools Parametric modeling tools Automatic view generation Mechanical symbol libraries CAD/CAM functionality © Goodheart-Willcox Co., Inc.

Solid Modeling Building from primitives. Revolving 2D profiles. Extruding 2D profiles. Removing material. Sweep operations. Loft operations. © Goodheart-Willcox Co., Inc.

Extruded Solid Model © Goodheart-Willcox Co., Inc.

Revolved Solid Model © Goodheart-Willcox Co., Inc.

Swept Solid Model (Anthony J. Panozzo) © Goodheart-Willcox Co., Inc.

Parametric Modeling Model defined based on adjustable parameters. Parts added must conform to existing construction. Model may include constraints. Operation verified during process. © Goodheart-Willcox Co., Inc.

Parametric Modeling Program (Image Courtesy of SolidWorks Corporation) © Goodheart-Willcox Co., Inc.

Automatic View Generation Fills need to provide 2D drawings to manufacturing personnel. Orthographic views most common. Section, auxiliary, and pictorial views may also be generated. © Goodheart-Willcox Co., Inc.

Computer-Aided Manufacturing Uses CAD data in computer numerical control (CNC) operations. Typically used by machining centers. Tooling movement and speed controlled automatically. Design data verified before machining. © Goodheart-Willcox Co., Inc.

CAD/CAM Software Program (EdgeCAM/Pathtrace) © Goodheart-Willcox Co., Inc.

AEC CAD Packages Designed for specific AEC fields. Special features added to general CAD tools. Used in both 2D and 3D drawing. © Goodheart-Willcox Co., Inc.

AEC CAD Package Features Automatic schedule generation Space diagram creation Stair generation Hatch pattern generation Wall creation Symbol libraries © Goodheart-Willcox Co., Inc.

Space Diagram Conversion © Goodheart-Willcox Co., Inc.

Common AEC Symbol Libraries Doors and windows Structural members Plumbing fixtures and fittings Electrical fixtures HVAC components Landscaping features © Goodheart-Willcox Co., Inc.

Common AEC Symbol Libraries (Cont.) Furniture and appliances Title symbols Construction details Vehicles © Goodheart-Willcox Co., Inc.

Door and Window Symbols © Goodheart-Willcox Co., Inc.

Building Information Modeling (BIM) Form of parametric modeling. Used in more advanced AEC CAD programs. Data stored for each construction system in structure. Components added alter existing structure. Result may be called virtual building. © Goodheart-Willcox Co., Inc.

Building Information Modeling Features Cost analysis tools Automatic generation of plan drawings Automatic schedule generation © Goodheart-Willcox Co., Inc.

Building Information Modeling Program (Autodesk, Inc.) © Goodheart-Willcox Co., Inc.

Review Questions 1. A symbol _____ is a collection of standard shapes and symbols used in a particular CAD application. library © Goodheart-Willcox Co., Inc.

Review Questions 2. A computer mouse is an example of a(n) _____ device. input © Goodheart-Willcox Co., Inc.

Review Questions 3. A(n) _____ prints object lines on drawings as vectors. A. laser printer B. inkjet printer C. inkjet plotter D. pen plotter D. pen plotter © Goodheart-Willcox Co., Inc.

Review Questions 4. Which of the following is not a typical feature found in a general purpose CAD package? A. Hatch pattern generation B. Automated dimensioning C. Editing functions D. Building information modeling (BIM) D. Building information modeling (BIM) © Goodheart-Willcox Co., Inc.

Review Questions 5. _____ are similar to transparent drawing sheets on which you can draw. A. Hatch patterns B. Layers C. Linetypes D. Drawing aids B. Layers © Goodheart-Willcox Co., Inc.

Review Questions 6. A _____ is a solid model created by extruding a profile along a path. A. sweep B. primitive C. revolution D. union A. sweep © Goodheart-Willcox Co., Inc.

Review Questions 7. Special controls called _____ are used in parametric modeling to define size and location dimensions to establish spatial relationships. constraints © Goodheart-Willcox Co., Inc.

Review Questions 8. A(n) _____ is created by extruding one or more profiles along a special type of path called a rail. loft © Goodheart-Willcox Co., Inc.

Review Questions Which type of CAD program is best suited for automated manufacturing? A. Building information modeling (BIM) program B. General purpose CAD package C. CAD/CAM program D. AEC CAD package C. CAD/CAM program © Goodheart-Willcox Co., Inc.

Glossary CAD CAD workstation Acronym for computer-aided drafting. The equipment included in a computer-aided drafting system. A typical workstation includes a computer or processor, monitor, graphics adapter, input and pointing device, and hard copy device. © Goodheart-Willcox Co., Inc.

Glossary Central processing unit (CPU) Command The primary working center of a computer, where all of the controlling functions and calculations take place. A CPU contains the processor, RAM, and input/output interfaces. Command An instruction to a computer that achieves a function when entered. © Goodheart-Willcox Co., Inc.

Glossary Computer-aided manufacturing (CAM) An automated manufacturing process in which drawing data from a CAD system is used to control the operation of computer numerical control (CNC) machines. Computer numerical control (CNC) A computer-operated means of controlling the movement of machine tools. © Goodheart-Willcox Co., Inc.

Glossary Constraints Drawing aids Special controls that define size and location dimensions to establish spatial relationships between the individual features of a part. Drawing aids CAD tools that simplify the tasks of locating positions on screen and on existing objects. © Goodheart-Willcox Co., Inc.

Glossary Inkjet plotters Inkjet printers Raster output devices used for quick production of large-format prints of CAD drawings. Inkjet printers Raster output devices used for quick production of small-size prints of CAD drawings. © Goodheart-Willcox Co., Inc.

Glossary Input device Layers A computer device (such as a keyboard) used to enter information into a computer. Layers On a CAD drawing, user-defined settings that permit the various parts of a drawing to be separated into different layers or “sheets,” much like the transparent drawing sheets in overlay drafting. © Goodheart-Willcox Co., Inc.

Glossary Loft A three-dimensional object created by extruding one or more cross-sectional shapes along a path. Network A group of individual computers connected to share information and resources. © Goodheart-Willcox Co., Inc.

Glossary Output device Parametric modeling A computer device used to display a drawing or produce hard copy. Parametric modeling A form of 3D-based CAD modeling in which user-defined geometric dimensions control the size and shape of objects and may be altered to change dimensional and spatial relationships. © Goodheart-Willcox Co., Inc.

Glossary Pen plotter A traditional vector output device used for generating large-format prints of CAD drawings. A pen plotter uses one or more pens to trace the object lines and “plot” the CAD drawing. © Goodheart-Willcox Co., Inc.

Glossary Primitives In CAD modeling applications, building elements drawn to form the basic shapes of a three-dimensional model. Primitives include boxes, cylinders, spheres, and cones. © Goodheart-Willcox Co., Inc.

Glossary Rendering Software Finishing a presentation drawing to give it a realistic appearance. The term rendering also refers to the actual drawing. Software A program used to instruct a computer to perform intended tasks. © Goodheart-Willcox Co., Inc.

Glossary Solid model Surface model A CAD-generated drawing defined with volume and mass to represent the solid mass of an object. Surface model A CAD-generated drawing defined as a wireframe with “skin” placed over the model to represent object surfaces. © Goodheart-Willcox Co., Inc.

Glossary Sweep Symbol library A three-dimensional object created by extruding a profile along a path. Symbol library In CAD applications, a collection of standard shapes and symbols typically grouped by application for use on drawings. © Goodheart-Willcox Co., Inc.