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CHAPTER 3

CHAPTER 3. Computer-Aided Design and Drafting (CADD). Learning Objectives. Define CADD and CAD Describe the CADD workstation and peripheral equipment Identify common CADD software manufactures and products Describe and compare CADD formats

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CHAPTER 3

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  1. CHAPTER 3 Computer-Aided Design and Drafting (CADD)

  2. Learning Objectives • Define CADD and CAD • Describe the CADD workstation and peripheral equipment • Identify common CADD software manufactures and products • Describe and compare CADD formats • Identify disciplines and industry concepts related to CADD

  3. Learning Objectives • Explain the use of animation and virtual reality in the design process • Demonstrate an understanding of basic CADD techniques including drawing and editing, line standards and layers, reusing content, plotting, file templates, and storing and managing files • Explain basic surface and solid modeling techniques

  4. Learning Objectives • Demonstrate an understanding of parametric solid modeling • Identify, describe, and use national CADD standards • Discuss issues related to productivity with CADD • Describe sustainable design and CAD practices

  5. Computer-Aided Design and Drafting (CADD) • Entire range of design and drafting with the aid of a computer • Computer-aided design (CAD) • Computer-aided drafting (CAD) • Used by several industries and most engineering and architectural related disciplines

  6. CADD Workstation • Hardware • Computer provides: • Data processing • Calculations • Communication with peripheral equipment

  7. CADD Software Products • Numerous and constantly changing • Many CADD software manufactures • Rapidly evolving CADD market

  8. CADD Software Products • General-purpose • Mechanical computer aided design (MCAD) • Other disciplines such as architectural, civil, structural • Software packages • Product lifecycle management (PLM)

  9. Common CADD Software Manufactures • Alibre, Inc. • Ashlar-Vellum • Autodesk, Inc. • Bentley Systems, Inc. • DassaultSystèmes • Google Inc. • GRAPHISOFT • IMSI/Design, LLC • Intergraph • IronCAD • Kubotek Corporation • Parametric Technology Corporation • Siemens Corporation

  10. Common CADD Formats • 2-D drawings • 3-D wireframe models • 3-D surface models • 3-D solid models

  11. Choosing a CADD Format • Design and drafting practices • Project requirements • Collaboration and communication • Software and training costs • Known industry standard product • Stability and usability • Support and training • Personal preference

  12. Two-Dimensional (2-D) Drawings • Established and often required design and drafting format • Common in all engineering and architectural industries and related disciplines • Describes design intent and product requirements • Can provide computer numerical control (CNC) machine code

  13. 2-D Drawings

  14. Three-Dimensional (3-D) Wireframe Models • Basic 3-D CAD model • Include object edges and vertices • Can provide geometry for: • 2-D drawings • 3-D computer numerical control (CNC) machine code • Replaced by 3-D surface and solid modeling

  15. 3-D Wireframe Models

  16. 3-D Surface Models • Include object edges, vertices, and surfaces • Complex curves and forms • Can provide geometry for: • 2-D drawings • 3-D solid models • 3-D computer numerical control (CNC) machine code

  17. 3-D Surface Models

  18. 3-D Solid Models • Most complex CAD format • Include object edges, vertices, surfaces, and mass • Exact digital representation of a product • May require some surface modeling • Offer engineering analysis and testing • Can provide geometry for: • 2-D drawings • 3-D computer numerical control (CNC) machine code

  19. 3-D Solid Models

  20. Industry and CADD • CADD can store many forms of data • CADD supports: • Manufacturing • Marketing • Sales • Service • Maintenance

  21. Product Lifecycle Management (PLM) • Supported by CADD • PLM software helps coordinate: • Design and manufacturing • Visualization and presentation • Maintenance and disassembly

  22. Web-Based Collaboration • Common to modern design and drafting • Supports the design and documentation process • Uses product data management (PDM) systems • Allows for increased outsourcing

  23. Prototyping • Prototype • Helps confirm a design • Typically occurs in the development phase of the design process

  24. Prototyping • Digital prototype (shown) • Rapid prototyping • Rapid injection molding • Subtractive Rapid Prototyping • Conventional machining

  25. Computer-Aided Engineering (CAE) • Involves: • CAD • Computer-aided industrial design (CAID) • CAD/CAM • CNC • CIM • PDM • Web-based collaboration

  26. Animation • Engineering animations • Basic element of product design and analysis • eLearning animations • Additional classroom learning tool or an online or distance learning presentation • Entertainment animations • Movies, television, and video games

  27. Computer-Aided Manufacturing (CAM) • Major innovation • Common process • Helps produce consistent and quality products • Computer-aided design/computer-aided manufacturing (CAD/CAM) • Computer numerical control (CNC)

  28. Computer-Integrated Manufacturing (CIM) • Computer and software controls most, if not all, portions of manufacturing • Incorporates CAD, CAM, robotics, electronics, hydraulics, pneumatics, computer programming, and process control

  29. Additional CADD Applications • Sales and marketing materials • Technical publications • Training documents • Product brochures • Installation and service manuals • Technical illustration (shown)

  30. Virtual Reality (VR) • Allows one or more people to move and react in a computer-simulated environment • Provides interaction with a model during the design process • Requires special interface devices • Walk-through • Fly-through

  31. VR Applications and Devices • Through-the-window VR (passive VR) • Head Mounted Display (HMD) • Binocular Omni-Orientation Monitor (BOOM) • Cave Automatic Virtual Environment (CAVE) • Haptic Interface • Web-Enabled Virtual Reality Modeling Language (VRML)

  32. Basic CADD Techniques • Drawing and Editing • Line Standards and Layers • Reusing Content • Plotting • File Templates • Storing and Managing Files

  33. Drawing and Editing • Commands for creating and modifying all elements of a drawing • Techniques vary depending on: • CADD software • Preferred design techniques

  34. Drawing and Editing

  35. Line Standards and Layers • Help organize and assign properties to objects • Separate objects into logical groups for formatting and display purposes

  36. Line Standards and Layers

  37. Example Mechanical Drafting Layers

  38. Reusing Content • CADD offers the ability to reuse: • Objects and object properties • Text and dimension settings • Drafting symbols • Sheets • Typical drawing details

  39. Plotting a Hard Copy • Often required • Creates a plot that can be viewed and marked without having a computer • Each CADD system uses a specific method to plot • Plotting theory is similar • Electronic plotting (exporting)

  40. Drawing Scale and Scale Factor • Important consideration when plotting • Automated by most CADD software, • Remains an important concept • Example application: • A 1:4 scale drawing has a scale factor of 4 (4  1 = 4) • Multiply the scale factor of 4 by values such as text height of .12 in. (3 mm) to find the .48 in. (12 mm) scaled text height

  41. File Templates • Preset settings for specific applications • Standard items required for multiple projects • Save time • Improve consistency

  42. Common Elements of a File Template • Units settings • Drawing and design settings and aids • Layers • Color, material, and lighting standards • Annotation standards • Common symbols • Display settings • Sheets and sheet items • Plot settings

  43. Storing and Managing Files • Save files immediately after you begin work • Save at least every 10 to 15 minutes • Develop an organized structure of file folders • Use a specific file naming system • Follow established file management techniques

  44. Surface Modeling Techniques • Polygonal modeling • Surfaces are quick and easy to modify • Common for character design for games • NURBS • Non-uniform rational basis spline • Non-uniform rational B-spline • Accurate curves and surfaces • Used by most CAD systems

  45. NURB Geometry • Complex mathematical spline representation with control points • Change control points to alter the curve

  46. NURB Geometry

  47. Direct Surface Modeling

  48. Procedural Surface Modeling

  49. Solid Primitives • Boolean operations • Also apply to more complex solid models

  50. Feature-Based Solid Modeling • Construct solid models using intuitive feature tools • Often begins with a 2-D sketch • Sketch used to develop a sketched feature • Additional features add or subtract solid material

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