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Computer-Aided Design and Drafting (CADD)

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Title: PowerPoint Presentation Author: tl user Last modified by: jeggemeyer Created Date: 10/19/2010 3:06:47 PM Document presentation format: On-screen Show (4:3) – PowerPoint PPT presentation

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Title: Computer-Aided Design and Drafting (CADD)


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.
  • Dassault Systèmes
  • 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
Layer Name Line Type Line Weight Color
Object Solid (Continuous) .02 in. (0.6 mm) Black
Hidden Hidden (Dashed) .01 in. (0.3 mm) Blue
Center Center .01 in. (0.3 mm) Green
Dimension Solid (Continuous) .01 in. (0.3 mm) Red
Construction Solid (Continuous) .01 in. (0.3 mm) Yellow
Border Solid (Continuous) .02 in. (0.6 mm) Black
Phantom Phantom .01 in. (0.3 mm) Magenta
Section Solid (Continuous) .01 in. (0.3 mm) Brown
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 14 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

51
Parametric Solid Models
  • Most common feature-based solid models
  • Often store model history
  • History-based solid modeling
  • Captures design intent using parameters
  • Maintains design constraints

52
History-Free Solid Modeling
  • Often associated with basic solids (dumb solids)
  • Makes design changes easy
  • Helps support collaboration
  • Explicit modeling

53
Parametric Solid Model Work Environments
  • Part
  • Assembly (subassemblies and assembly)

54
Part Model Elements
  • Sketch
  • Sketched feature
  • Placed (built-in, added, automated) features
  • Feature pattern
  • Reference (work, reference geometry) features
  • Catalog (library) feature

55
Assembly Modeling
  • Add and constrain existing components
  • Bottom-up design
  • Create components within an assembly file
    (in-place)
  • Top-down design
  • Assembly constraints (mates)

56
Assembly Modeling
57
Extracting Drawing Content from Models
  • Editing the model adjusts the corresponding
    drawing
  • Some edits to the drawing modify the linked model

58
CADD Standards
  • Design and drafting requirements
  • Appearance
  • Technique
  • Operating procedures
  • Record keeping method

59
CADD Standards
  • File storage, naming, and backup
  • File templates
  • Units of measurement
  • Layout characteristics
  • Borders and title blocks
  • Symbols
  • Layers, and text, table, and dimension styles
  • Plot styles and plotting

60
CADD Standards
  • American Society of Mechanical Engineers (ASME)
    standards
  • CADD Skill Standards
  • United States National CAD Standard

61
Design Planning
  • Important and productive time
  • Determines how you approach a project
  • Without proper planning you may become frustrated
    and waste time

62
Design Planning
  • Helps establish
  • Drawing layout
  • Drafting settings
  • How and when to perform specific tasks
  • What objects and symbols to create
  • The best use of CADD and equipment
  • An even workload

63
Ergonomic Workstation
  • Helps prevent most computer-related injuries

64
Positive Work Habits
  • Concentrate on good posture
  • Keep your stress level low
  • Take periodic breaks
  • Apply stretching and other exercises
  • Locate noisy plotters in a separate room and keep
    other noise to a minimum
  • Ensure adequate air-conditioning and ventilation

65
Stretches to Help Avoid Repetitive Injury
66
Glossary
  • Animation
  • The process of making drawings or models move and
    change according to a sequence of predefined
    images.
  • Assembly constraints (mates)
  • Establish geometric relationships and positions
    between components, define the desired movement
    between components, and identify relationships
    between the transitioning path of a fixed
    component and a component moving along the path.
  • Basic solids (dumb solids)
  • Non-parametric solids.

67
Glossary
  • Boolean operations
  • In geometry, the process of adding and
    subtracting primitive shapes.
  • Bottom-up design
  • A design approach that brings individual
    components together to form an assembly.
  • Computer numerical control (CNC)
  • Also known as numerical control (NC), is the
    control of a process or machine by encoded
    commands that are commonly prepared by a computer.

68
Glossary
  • Computer-aided design (CAD)
  • Uses computers for design.
  • Computer-aided design and drafting (CADD)
  • The process of using a computer with CADD
    software for design and drafting applications.
  • Computer-aided design/computer-aided
    manufacturing (CAD/CAM)
  • A part is designed on the computer and
    transmitted directly to computer-driven machine
    tools that manufacture the part.

69
Glossary
  • Computer-aided drafting (CAD)
  • Uses computers for drafting.
  • Computer-aided engineering (CAE)
  • The method of using computers in design,
    analysis, and manufacturing of a product,
    process, or project.
  • Computer-aided manufacturing (CAM)
  • Uses computers to assist in the creation or
    modification of manufacturing control data,
    plans, or operations, and to operate machine
    tools.

70
Glossary
  • Digital prototype
  • A computer-generated model or original design
    that has not been released for production.
  • Ergonomics
  • The science of adapting the work environment to
    suit the needs of the worker.
  • Explicit modeling
  • Typically refers to direct, history-free
    modeling. Direct solid modeling describes the
    process of using more interactive methods, such
    as pushing or pulling on an edge or face, to
    create and modify geometry.

71
Glossary
  • File management
  • The methods and processes of creating a
    management system, then storing, retrieving, and
    maintaining the files within the guidelines of
    the computer system.
  • File template (template)
  • A file that stores standard file settings and
    objects for use in a new file.
  • Fly-through
  • Similar to walk-through, but the camera is like a
    helicopter flying through the area.

72
Glossary
  • Hard copy
  • A physical drawing created on paper or some other
    media by a printer or plotter.
  • Hardware
  • The physical components of a computer system,
    such as the computer, monitor, keyboard, mouse,
    and printer.
  • Outsourcing
  • Sending elements of a project to subcontractors
    for completion.

73
Glossary
  • Parameters
  • Geometric characteristics and dimensions that
    control the size, shape, and position of model
    geometry. A database stores and allows you to
    manage all parameters.
  • Parametric
  • The method of using parameters and constraints to
    drive object size and location to produce designs
    with features that adapt to changes made to other
    features.
  • Peripheral
  • An external computer hardware device that uses
    the computer to perform functions that the
    computer cannot handle.

74
Glossary
  • Polygonal modeling
  • A basic form of surface modeling that produces
    lower quality surfaces without precise curvature
    control.
  • Product data management (PDM)
  • The process of organizing and monitoring data
    related to a product, such as drawings, models,
    specifications, and other associated documents.
  • Product lifecycle management (PLM)
  • The method of managing the entire lifecycle of a
    product from the initial concept, through
    development and manufacture, to discontinuing or
    replacing the product.

75
Glossary
  • Prototype
  • A functional model of a design and is used as the
    basis for continuing the production of the final
    part or assembly.
  • Rapid injection molding
  • An automated process of designing and
    manufacturing molds based on customer supplied
    3-D CAD part models.
  • Rapid prototyping
  • A manufacturing process by which a solid physical
    model of a part is made directly from 3-D CAD
    model data, without any special tooling.

76
Glossary
  • Scale factor
  • The reciprocal of the drawing scale, and is used
    in the proper scaling of various objects such as
    text, dimensions, and graphic patterns.
  • Software
  • The program or instructions that enable a
    computer to perform specific functions to
    accomplish a task.
  • Solid primitives
  • Objects such as boxes, cones, spheres, and
    cylinders that you combine, subtract, and edit to
    produce a final model.

77
Glossary
  • Spline
  • A curve that uses a series of control points and
    other mathematical principles to define the
    location and form of the curve.
  • Subtractive Rapid Prototyping
  • Uses proprietary software running on large-scale
    computers to translate a 3-D CAD design into
    instructions for high-speed CNC milling
    equipment.
  • Surface
  • An outer boundary of an object that connects to
    edges and vertices.

78
Glossary
  • Three-dimensional (3-D)
  • An object having width, height, and depth
    dimensions.
  • Top-down design
  • A design approach in which the assembly controls,
    or produces, individual components.
  • Two-dimensional (2-D)
  • A view having only width and height, width and
    length, or height and length dimensions.

79
Glossary
  • Vertices
  • Plural for vertex, which is the point where edges
    intersect.
  • Virtual reality (VR)
  • A world that appears to be a real world, having
    many of the properties of a real or actual world.
  • Walk-through
  • Characterized as a camera in a computer program
    that is set up like a person walking through a
    building, around a product or building, or
    through a landscape.
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