Homework Assignment 4. Assigned Apr 1, Due April 8.

Question 1:

Consider the problem of computing whether or not a legal solid is the null object (i.e. zero volume). Given a model represented as a CSG model, how will check for null object. Give an outline and not a detailed description.

Question 2:

Consider the problem of point classification: Given a valid solid with non-zero volume, you need to know whether the point is inside or outside. How will you perform this test for:

• (a) A solid represented as a CSG expression.
• (b) A B-rep solid.

Question 3:

This is exercise 16.1 from page 813 of Foley, et al. It has three parts.

• (a) Describe the difference in appearance you expect between a Phong illumination model that used (N dot H)^n and one that used (R dot V)^n.
• (b) Show that alpha = 2 beta when all vectors of Fig 16.12 (p. 731) are coplanar.
• (c) Show that this relationship is NOT true in general.