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CAD PowerPoint Presentation

CAD

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CAD

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    1. CAD/CAM/CAE Systems GE393 Computer Aided Design, Analysis & Prototyping

    2. Product Development To compete, new products must continuously: Improve quality Reduce cost Shorten lead time

    3. Product Modeling Design model Actual design geometry Analysis model Abstraction of the geometric model Eliminate details Dimensional reduction (3D 2D, 1D) Employ symmetry

    4. CAD, CAE, and CAM Computer-aided design (CAD) Define design geometry Computer-aided engineering (CAE) Analyze CAD geometry Computer-aided manufacture (CAM) Plan, manage, control manufacturing operations

    5. Graphics Device Hardware Display processing unit Display device (monitor) Input devices (mouse, keyboard, etc) DPU positions images on monitor screen Accepts graphics commands Produces electron beams Transmits (maps) beams to screenDPU positions images on monitor screen Accepts graphics commands Produces electron beams Transmits (maps) beams to screen

    6. Kinds of Graphics Devices Vector-refresh Line drawing device High resolution, straight lines Random refresh Raster-refresh Point plotting device Aliasing problems Regular, repetitive refresh High performance to cost ratio

    7. Vector-Refresh 3 Components Display processing unit Display buffer CRT Display buffer Hardware (memory) Display list Software (commands) Refresh (redrawing) time Image repeatedly drawn < 30 Hz, flicker

    8. Raster Graphics Screen image represented by an array of dots (pixels) Raster image stored in frame buffer a portion of memory Dot size determines resolution Refresh required

    9. Raster Graphics Display Processor Generates and stores raster image in frame buffer Reads frame buffer contents and casts electron beams onto display device

    10. Raster Scanning Scan lines Refresh time constant 30 Hz (TV) 60 Hz (high end)

    11. Frame Buffer Bit Planes (Color) 1-bit plane (bitmap 1 bit per pixel) Black and white 3-bit planes 8 (23) colors 8-bit planes 256 (28) colors 24-bit planes 16,777,216 ((28)3 or 224) colors

    12. 3-Bit Plane Color

    13. 3-Bit Plane Color Table

    14. 24-Bit Plane Color 8 bit planes for each color (RGB) Resolution of 8 Inside monitor tube 3 kinds of phosphor (emit R,G, or B light) Arranged in a triangular (RGB) pattern, each triangular segment maps to a single dot in frame buffer8 bit planes for each color (RGB) Resolution of 8 Inside monitor tube 3 kinds of phosphor (emit R,G, or B light) Arranged in a triangular (RGB) pattern, each triangular segment maps to a single dot in frame buffer

    15. CAD/CAM/CAE Systems Computer Aided Design, Analysis & Prototyping