Re: Strange problem with coordindex

Syndesis Corporation ([email protected])
Wed, 14 Jun 1995 16:28:06 -0500


"Chris Marrin" <[email protected]> writes:
>Very little is said about normal generation in VRML 1.0. We should
>rectify this in 1.1. I'd like to suggest adding a statement that, by
>default, VRML generates counterclockwise normals.

Yes, it doesn't hurt to be specific. It's also important to
describe exactly which edges of the polygon are used to calc
that normal. The choice is not ob Wavefront uses points 0, 1, 2. LightWave uses N-1, 0, 1.
Sense8 averages the normals at all corners.

We handle this sort of re-ordering of points in face enum lists
in InterChange, in order to properly move polygons from one format
to another. The difference between Wavefront and LightWave as
described above is subtle; 99% of the time you can do it the "wrong"
way and it'll still render correctly, depending heavily on whether
the artist like

- John Fa> t