Sunday, 4 December 2016

IPU BCA Semester 5 - Computer Graphics - Cavalier vs. Cabinet projections

Computer Graphics 

(Questions and Answers)

IPU BCA Semester 5 - Computer Graphics - Cavalier vs. Cabinet projections

Question: Distinguish between the following:

(i) Cavalier vs. cabinet projections

(ii) 2-D clipping vs. 3-D clipping

Answer:
CAVALIER VS CABINET
Cavalier Projections Cabinet Projections
1) The direction of projection makes an angle of 45 degrees with the view plane. 1) The direction of projection makes an angle of 63.4 degrees with the view plane.
2) The projection of a line perpendicular to viewing surface has the same length as the line. 2) Lines perpendicular to the viewing
surface are projected at one-half their actual length.
3) A cavalier projection is obtained when the angle between oblique and the plane of projection is 45 degrees. 3) A cabinet projection is obtained when the angle between oblique and the plane of projection is cot-1(1/2)
4) The foreshortening factors for all three principal axes are equal. 4) An oblique projection, for which
the foreshortening factor for edges perpendicular to the plane of projection is one-half, is obtained.
5) The resulting figure appears too thick. 5) The resulting figure is not very thick.



Answer: ii)
2D CLIPPING VS 3D CLIPPING
Parameters 2 D Clipping 3 D Clipping
Same graphical representation 1) What a person can draw on paper, could simply be drawn exactly on the computer screen. 1) Drawing involves z-direction.
Conceptual Design 2) It is less suitable for Conceptual
Understanding of Design and is used mainly for engineering drawings.
2) It has a better understanding of conceptual design.
Design Ambiguity 3) Some misinterpretations of the design can be there. 3) It removes design ambiguity.There are less misinterpretations.
Simulations 4) Not much suitable for simulations. 4) Simulations are highly appropriate through 3D clipping.

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