Week 6 - 3D To 2D

Question 1

Define The Purpose Of The Projection Transformation

Answer 1

Transforms 3D Points To 2D Points.

Question 2

State The Two Basic Types Of Projection Transformation.

Answer 2

• Parallel Projection.

- Perspective Projection.

Question 3

What Is The Defining Feature Of Parallel Projection?

Answer 3

Object Proportion Is Preserved.

Question 4

What Is The Defining Feature Of Perspective Projection?

Answer 4

Object Proprtion Is NOT Preserved.

Question 5

State The Correction For Aspect Ration In Order To Ensure The Projection Transformation Is Scaled To The Viewport Dimensions.

Answer 5

Aspect Ratio = Window Width/Window Height.

Question 6

Define The Perspective Projection Matrix

Answer 6

( d/a 0 0 0
0 d 0 0
0 0 d 0
0 0 1 0 )

Question 7

Define The Perspective Matrix With A Field Of View Of 90 Degrees.

Answer 7

( 1/a 0 0 0
0 1 0 0
0 0 1 0
0 0 1 0 )

Question 8

Explain The Purpose Of Dehmogenisation

Answer 8

Convert The Matrix From 3D To 2D

Question 9

Explain How To Dehomogenise

Answer 9

Divide All The Perspective Translated Vertex Components By _w.

Question 10

Define The Screen Transformation Matrix

Answer 10

width/2 0 0 width/2
0 -height/2 0 height/2
0 0 d/2 d/2
0 0 0 1

Question 11

Define The Purpose Of The Screen Transformation

Answer 11

Locate The Centre Of The Image, centre it And Scale It To The viewport.