Practical Algorithms for 3D Computer Graphics, 2nd Edition

10.9. Boolean modeling 425

Edge on view of facets in the tool list

Facet

in the

work list

4

4

4

4

3

3

1

1

3

3

A

B

E

E´

X

3

4

3

4

3

4

C

2

1

2

1

2

1

1

1

2

2

2

2

(a)

(e) (f) (g) (h)

(b) (c) (d)

Figure 10.51: This example is discu s s ed in the text.

On comparing triangulation (f) (figure 10.51) with the view (a) it can be seen

that the edge joining points (2 −4) lies in the plane of on e of the Tool facets and

is therefore part of the line of intersection. Of the other internal edges created

in Phase 2 it is only the edge E, joining point 2 to vertex B (B is a vertex of

the original triangle), which still intersects a facet in the Tool list. All the other

edges do not cross a facet in the T