View Full Version : Dissapearing polys in Layout

04-18-2003, 10:36 PM
Yeah I've recently encountered a problem with dissapearing polys in Layout that have strange shape. Most commonly the faces that dissapear have the mysterious Triangle wire that cannot be seen even with wireframe view. When I turn my model in some positions these faces will dissapear but when I change the postion to soem other the faces reapear. I thought it had something to do with welding points but that hasn't helped.

I do know that it has something to do with the MIRROR function as in the beginning I had two symetrical polys and used the MOVE tool on them rather than smooth shift and this caused one side to create the weird split polygon. So I Erased one side and mirrored the other side and welded the mirrored polygons but now have this dissapearing poly problem.

The Picture I am attaching is the mysterious split polygon bug the dotted line indicating the split where it would seemt o be a wireframe but is not. The line doesn't exist, only the polygon deformation. The 3D side shows how the polygon seems to look like two polys but is really just One messed up polygon thats till has four sides.

I need help on how to correct the dissapearing poly's problem. BTW the polygons don't dissapear in modeller only layout.

Oh and its lightwave 7.0 if that helps.

04-19-2003, 06:12 PM
Nobody knows what or how to fix this issue?

John Fornasar
04-19-2003, 09:10 PM
Not a bug, it's LW's way of telling you that you have non-planar polys in your model.
Bring it back into Modeler and clean it up (hit "w", check the stats)

or duplicate polys...

and it'll be better if you post an actual screen shot of any problem you might have...

04-20-2003, 01:02 AM
Eh...heh...yeah, um, lol...Crazy I tell you. For some reason I have approxamately 13,000 Non-Planar polygons. ???, It was not like that a few days ago I must of clicked some function on accident or something. Anyway to fix this?

04-20-2003, 01:19 AM
Eh its ok for I have just fixed the dissapearing sectors with new built triangles and they are no longer dissapearing. yeah it has what seems to be many many duplicated poly's but you can't actually notice them and I still have smooth movement in layout and its not intended for a game or anything so what the heck, I'll just keep it the way it is. I didn't even know I had so many non-planar poly's until I looked today but it obviously made no difference as I didn't notice any change when I reopenned the project. Anyway, it was only like a total of four poly's tahtw ere actually dissapearing.

yeah I'm cheap

Elmar Moelzer
04-20-2003, 02:56 PM
LW is capable of dealing with non- planar- polygons pretty well, but if they exceed a certain "flatness", even LW can make problems. To get rid of the easily just select them in the statistics and tripple them.
To get rid of duplicate polys just use the unify polgons tool in modeler.

04-20-2003, 04:09 PM
Well the cause is pretty simple i guess, in Layout every polygon has only one normal vector, and backfacing is determined by the normal. But if it isn't flat, than there can be parts that should be visible but aren't because they are not perpendicular to the normal.
In Layout there is only visible or backfacing for a whole polygon.
Just triangulate non-planar polys...they don't make much sense anyway IMHO (unless they are sub patches) because they get lit wrong...since they are considered planar although it's not the case.

Modeler seems to do the backfacing on a triangulated mesh, but lighting still on the polygon normal.