Lecture 2 (Perspective and Polygonal Geometry)

Question 1

WTF is the ‘virtual camera’? What camera model is it based off of?

Answer 1

• Camera in the scene
• > mimics the pinhole camera model
• > Mapping from 3D space to 2D image

Question 2

WTF is the pinhole camera model?

Answer 2

Light comes in through a small hole and it is reflected AND flipped to form the image

Question 3

How many camera perspectives are there and what are they?

Answer 3

• One-point perspective
• Two-point perspective
• Three-point perspective
  
  • > None of the dimensions converging are parallel

The difference is in the number of vanishing points
-> Determines which axioms converge

Question 4

What is the difference in the different camera perspectives?

Answer 4

Number of vanishing points

Question 5

Which polygon is best used to model computer graphics? Why?

Answer 5

Triangles because you can make anything from a triangle.

Question 6

Higher number of polygons = ???

Answer 6

More detail

Question 7

Why does distance matter with regards to level of detail?

Answer 7

The greater the distance a viewer is to the object, the less detail required, therefore, fewer number of polygons, therefore less computationally expensive to render.

Question 8

How are 3D objects projected onto 2D images?

Answer 8

X,Y,Z points in 3D world (voxels) are transformed into x,y pixels in a 2D image

Question 9

What are the three things needed to draw perspective geometry?

Answer 9

• Horizon line (eye level)
• Vanishing points
• Vanishing lines

Question 10

Define Polygon.

Answer 10

Any plane figure bounded by straight line segments.

- They are useful alone and as building blocks for approximating curved arcs and regions