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TEST 3 - CS458 
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Instructor Dr P Juell                                                           NAME_______________________ 
OPEN BOOK                                                                
	  Dec 16, 1998
200 points         
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1. (24)
Specify number in order from 1 (most computation to 8 (least computations)
for each of the following items.
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___ ray tracing
___ radiosity 
___ uniform surface 
___ painters algorithm (uniform surface shading)
___ Phong shading
___ Gouraud shading 
___ wire frame
___ wire frame with hidden line removal
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2. (10)
Describe (in English) what the following colors are:

in RGB (0,0,0)

in RGB (1,0,0)

in RGB (.5,0,.5)

in HSV (0,1,1)

in HSV (0,0,1)

3, (12)
Specify a minimal set of control points (in order) for a Bezier curve.
They are to create a reasonable circle with center at (1,1) and radius of 1.
(Specify the (x,y) values).
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4. (12)
Two programs (named A and B) are using different internal
representations of solid objects.  One is storing blobby object
parameters and the other is directly using octree descriptions of voxels.
Explain how you could determine by examing images which of the two internal 
representation is used.
(You have the normal GUI tools for a paint program and/or a high end
viewing program).
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5. (15)
For each of the following circle the item in the list that
goes with the first item:

Bresenham line algorithm: vector display, raster display

odd-even rule: items with boundaries, vector based data

dithering: anitalizaling, line drawing

extra item per pixal: octree, z-buffer

prospective transform: 3D viewing, shading

6. (15)
Images can be built using a paint program,
programs written using some standard, such as GKS/PHIGS/VTK,
or by building a file with embedded structure commands, such as files with
extensions vtk, wrl(for VRML) and others).
Sepcify for each a situation where it would be prefered 
over the other two.
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7. (14)
You have an object at (1,2,5).
Describe the sequence of homogeneous coordenat matrixes to change the
image with one with the item upsidedown at the same point.
(Do not use the direct change system used in vtk and VRML).
First give the sharthand notation (T(x,y,z)...) in the correct order.
Then give the full matrix notation, also in the correct order.
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8. (12)
Data has been collected on the forces on a beam.  At each of a number
of points on the beam, the amount of force and its direction have
been recorded.  It is desired to find areas where the forces change
quickly.  
What is a visiaulization what would be useful in this context?
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9. (16)
Assume you have
a control that changes a display from right hand
coordent system to left hand corrdent system.
What is one major difference a viewer would see between the two images?
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If the right hand rule for surfaces was changed to a left hand rule, 
with no other changes, what would be the effect?
(Note, depending on the system, you may or may not be able to 
see the effect of this).
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10. (12)
Draw an example of type 0 continuity but not type 1:
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Draw an example of type 1 continuity but not type 2:
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Draw an example of type 2 continuity:
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11. (16)
It is desired to create a movie of an ice cube melting.
You are doing this with computer graphics tehcniuqes.
Give two good techniques to get the desired effect.  
Specify the technique and what it will do
for the desired effect.
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12. (14)
What are two important reasons for building objects using structured notation?
(The notation will be used to embed parts of the structure).
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13. (8)
Why would the Gouraud shading model not be useful in esimating
specular highlights?
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14. (20)
Computer graphics has a trade off between image quality and computation time.
Breifly charactive this tradeoff.  
Give two techniques and where they fit into this tradeoff.
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