PDA

View Full Version : Twisted polys



ackees
12-01-2003, 04:03 PM
Do twisted polys cause problems in LW when you come to render later? To keep the poly count down I have left a number in, but I would hate to suffer later when they do not render in a complex scene, I could triple but should I? (the strange thing about these twisted polys is they tend to flip themselves when you subpatch them).
Am I making a rod for my own back?
Thanks.

FenrirWolf
12-01-2003, 04:16 PM
The points that make up the polygon are not co-planar. It's a problem with working with polygons of more than three sides. The manual calls them "catawampous" polygons.

Render-wise, I haven't noticed any problems with non-coplanar polygons and subpatches. I usually leave them in, as tripling them might create creases if you end up with a dreaded five-face point.

Still, they're annoying as the face normal isn't always easy for Lightwave to calculate -- as you mentioned, requiring manual flipping.

Macet01
12-01-2003, 04:16 PM
Non-planars, like the one that you have there tend to cause errors during rendering. What you may want to think about is tripling just the non planars prior to rendering. That should clear up some of the problems that you are having.

riki
12-01-2003, 06:43 PM
Normally if you tweek the points a little on the offending Polys you can minimise the problem.

I also use a 'planarize' lscript which I found here http://vbulletin.newtek.com/showthread.php?s=&postid=862

Points that are intersected by 5 vertices shouldn't be a problem. It's virtually impossible to avoid. As soon as you Bevel a Face (in a grid of Polys) you end up with 4 of these little buggers. Six or more connecting vertices though will definately cause problems.

ackees
12-02-2003, 03:26 AM
Thanks all, maybe I had better be safe than sorry. The stupid thing is I got my character to about 5000 polys but the teeth and gums are about to add 2000 polys.