Practical Algorithms for 3D Computer Graphics, 2nd Edition

10.4. Lofting 395

Repeat the following for all facets j in the n etwork {

[ Note that at this stage the list List(j) will have a

[ vertex identity for all three items in each element b ec a u s e

[ every side of all fa c ets will have been sub d ivid ed .

[ Note also that it is very important that a consistent ordering

[ of vertices for new fa c ets is maintained so that the surface

[ normal vectors will point in the outward direction for all facets.

Add three facets between the vertices below:

Facet 1) List(j).V

01

, List(j).V

12

, List(j).V

20

Facet 2) List(j).V

01

, P ol y(j).V id(1), List(j).V

12

Facet 3) List(j).V

12

, P ol y(j).V id(2), List(j).V

20

And three ...