Triangulating the wrong way

[killermiller]

Using Renderware exporter, and the tri-striping is driving me nuts. Here's the problem.

Looking at the image found here.

http://www.thekillermiller.com/temp/tri\_problem.gif

What you are looking at is a bunch of polygons with "triangles" displayed through the custom polygon display. The dashed lines in figure "A" show how the polygon will be triangulated once it's exported.

Yet I need it to look like it does in Figure "B"

Is there a way to select the face and switch the triangulation? Note the polygon is in quads. I don't want to cut it up, I just want to change the way maya reads the orientation of the quad.

a mel script or some method of changing these quads would be awesome.

thanks.

[gmask]

The only way I know of is to manually split the quad the way you want it to go.

[adamw19]

Goto Edit Polygons > Flip Triangle. I'm not sure if it's called Flip Triangle or Flip Triangle Edge. But that will flip it the right way that you want.

[gmask]

It's called Flip Triangle Edge.. I forgot about that one.

[killermiller]

You guys aren't really understanding my problem. Using "flip triangle" works once the quad has been split.

Maya already splits any quad even though you don't visibly see it. I need something to the effect of "flip triangle" but without having to manually triangluate the object first.

[gmask]

I understand the problem.. but I didn't test the flip triangle to see if it was an actually a solution for you.

What I don't understand is why you are adversed to just triangulating? Your renderer obviously has to triangulate.. all renderers do.

Is it that there are so many wrong ones that you don't wish to manually correct the bad ones?

[killermiller]

"Is it that there are so many wrong ones that you don't wish to manually correct the bad ones? "

Ya the image is just an example. I'll need to run about a million poly's through the mel script. For contract reasons, I can't show what I'm actually working on. I'm guessing it has something to do with the way the geomerty is being built. It's numbering the vertices for the mesh. I need to have vertices on the mesh renumbered for it to do what I want. Anybody?

[gmask]

When you say it what do you mean.. Maya? Which MEL script?

It's pou to fmy leagure but I suppose you could right a MEL script that would examine faces and try to make a better decision about which faces need to be triangulated which way but I would sor t of asume that if it were that easy then Maya might actually do a better job of it. THis is going to invovle some math to determien that based ont eh usrroundign faces that the tringle needs to be a valley or a ridge.. if the srounding faces are higher up then it's a valley.. if they are lower then you could assume it's a ridge. There are probably many instances where this may be hard to determine

[user_deleted]

yes, this problem has buged me for a long time, as there is no way to predict the tessellation preview while working in quad. And i don't think its fixable via mel.

And in my opinion maya has one of the worst triangle tessellations too, that is it doesn't equally divid quads base equal area.

[jeffd]

Yep, Maya triangulates into fans because that makes for the most optimal tri-stripping. Unfortunately, that is usually the exact opposite of what looks good for lighting or for a nice, clean mesh.

--JeffD