Computer Science 598d
Thought Exercise #4
Object Representations
Due: April 9, 1998

We have studied several different 3D object representations over the course of this semester, including scene graphs, polygonal meshes, curved surfaces, constructive solid geometry, BSP trees, voxels, and image-based reps.  Of course, no one of these representations is best for describing every type of object, for every operation, in every application.  For each of the following situations, please describe which object representation(s) you think is best for the object written in capital letters, and give a one or two sentence explanation why.
  1. Rendering images of a CLOUD.

  3. Rendering photorealistic images of a FOREST with thousands of trees and millions of leaves from arbitrary viewpoints inside the forest.

  5. Interactive visualization of a SOFA with soft cushions.

  7. Interactive visualization of a TEDDY BEAR with long fur.

  9. Interactive visualization of the TAJ MAHAL for educating school children.

  11. Interactive visualization of the interior of a proposed (not yet constructed) BUILDING design.

  13. Finding interferences (intersecting parts) in a proposed AIRPLANE engine design

  14. (e.g., finds pipes passing through one another).
  15. Checking for accessibility to different parts in a proposed AIRPLANE engine design
    (e.g., whether or not a repair person can reach a part with his/her hand)

  17. Determining the differences between two 3D models of a DESK.

  19. Avoiding collisions between the surfaces of a large CITY and the path of a viewer moving through it.

Please email me your answers at least one hour before class on Thursday, April 9.