What is CAD, Computer Graphics, The Design Process, Basic Graphics System, CRT (Cathode Ray Tube), Display Processor, Video-Display Devices

1. 1
CAD (Computer Aided Design)
Email: amittechnosoft@gmail.com

2. What is CAD
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 “CAD is the Application of graphics software and
computers to enhance to design of part product
model or assemblies from conceptualization to
documentation “.

3. Computer Graphics
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 Now a Days wide range of graphics hardware and
software systems is available .
 Graphics capabilities for both two dimensional
and three dimensional applications are common.
 we use a wide variety of interactive input deices
and graphics software's

4. Ingredient of Computer
Graphics
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 Computer graphics deals with all aspects of
creating images with a computer
 Hardware
 Software
 Applications

5. 5
 In this configuration is shown in and hardware
provides the input , computation, storage and
output functions
Fig. 1 Graphics software configuration
Architecture of Computer Graphics
Software

6. The Design Process
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 The process of designing basically consists of six
identifiable phases or steps.
 Recognition of need.
 Definition of Problem
 Synthesis
 Analysis and optimization
 Evaluation
 Presentation

7. Basic Graphics System
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Input devices
Output device
Image formed in FB
Graphic Tablet
Key Board
Mouse
Fig. 2 Basic Computer Graphics

8. CRT (Cathode Ray Tube)
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Can be used either as a line-drawing device
(calligraphic) or to display contents of frame
buffer (raster mode)
Fig. 3 CRT (Cathode Ray Tube)

9. Display Processor
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 Rather than have the host computer try to
refresh display use a special purpose computer
called a display processor (DPU)
 Graphics stored in display list (display file) on
display processor
 Host compiles display list and sends to DPU
Fig 4. Display Processor

10. Video-Display Devices
Refresh Cathode-Ray Tunes
Fig. 5 Basic design of a magnetic-deflection CRT

11. Video-Display Devices
Refresh Cathode-Ray Tunes
Fig. 6 Operation of an electron gun with an accelerating anode

12. Video-Display Devices
Refresh Cathode-Ray Tunes
Fig. 7 Electrostatic deflection of the electron beam in a CRT

13. Video-Display Devices
A raster –scan system displays an object as a set of
discrete points across each scan line.
Fig 8. Raster Scan System

14. Note at the Interlace mechanism of display: display the even lines
in
1/60 of a second and then display the odd lines in next 1/60
seconds.
Fig 9. Implementation of Raster Scan

15. Video-Display Devices
Fig.2-9 A random-scan system draws the component lines of an
object in any order specified.
Fig 10. Random scan System

16. Video-Display Devices
Operation of a delta-delta, shadow-mask CRT. Three electron guns,
aligned with the triangular color-dot patterns on the screen,
are directed to each dot triangle by a shadow mask.
Fig 10. Video display devices