Chapter 3

Question 1

translation

Answer 1

changing position

Question 2

rotation

Answer 2

changing orientation

Question 3

R3

Answer 3

virtual world which every point is repreented as a triple of real valued coordinatates(x,y,z)

Question 4

primitives

Answer 4

represetnations in a computer that are finite but each represents an infinite set of point (3d triangle)

Question 5

mesh;

Answer 5

numerous trangles arranged to model a complicated object

Question 6

questions about mesh representing objects

Answer 6

how to specify how each traingle looks when used by viewed, how to make object move, if object surface is curved then should use curved primitives?, is interior part of model or does object only have surface, is there effecient algorhm for determining which triangles are adjaacent to given triangle, should we avoid duplicating vertex coordinates that are common to neighboring triangles

Question 7

doubly connected edge list

Answer 7

half edge ata structure - depend on which operations are performed

Question 8

three data elements

Answer 8

faces, edges vertices

Question 9

coherent model

Answer 9

barrrier between inside and outisde of an object are formed then if fill inside with gas, could not leak out but if single traingle is removed, no longer a clear distinction between inside and outside of object

Question 10

polygon soup

Answer 10

jumble of traingles that dont fit ogether nicely

Question 11

two kinds of models

Answer 11

stationary and movable

Question 12

stationary models

Answer 12

keep same coordinates forever like streets

Question 13

moveable modesl

Answer 13

transformed into various potiions and orientation like vehicels

Question 14

two possible interpretations of transofrmation

Answer 14

original object - object moves or origin moves