Max is triangulating model differently when combined??

guitarguy00

Hey guys,

So I baked out my model consisting of two parts in Marmoset using different mesh names/bake groups so I did not have to explode the mesh prior to baking. I triangulated the mesh prior to baking using Max's export setting and everything baked fine. However when I later combined the two meshes in Max and exported using the triangulate function, Max flipped one triangle for some reason giving me a very distorted look,

Now I compared it to the original pre-combined mesh and it triangulated it differently in that one area. So I know why the shading is warped but don't know why Max would triangulate it differently on export just because I combined the two meshes. This has never happened before and I have made models with over 30 parts. Is there any way around this besides flipping the triangle manually?

poopipe

usually if you use a turn to poly modifier and tell it to keep faces convex you don't get issues . 


it is a bit odd though - maybe just a quirk of the maths .  your safest bet is to explicitly define that edge direction 

guitarguy00

poopipe said:

usually if you use a turn to poly modifier and tell it to keep faces convex you don't get issues . 


it is a bit odd though - maybe just a quirk of the maths .  your safest bet is to explicitly define that edge direction 

Thanks for that. I will definitely look into the turn-to-poly modifier as I have seen it used by Arrimus and others and it looks pretty useful. 

It is very strange especially considering it is a completely flat area. I ended up just triangulating that part manually before combining like you said and it solved it. 

Mark Dygert

Triangulating your mesh before you bake is a good idea. Any edge that isn't visible, isn't set in stone and apps take those undefined edges and will interpret those any way they see fit. Most apps will stripe triangles from bottom left corner to upper right. Maya strictly enforces this and doesn't let you "go against the grain". Max is a bit different in that it allows you flip undefined edges any way you want and it will just preserve them while you're in the app. However if you export them as undefined then they can be re-striped because apps assume you don't care about the non-visible edges and they do it for performance reasons.

Triangulate before you bake.
Apply the the turn to poly modifier, set the max number of faces to 3. After you export you can delete the modifier and the triangulation goes away. IF you're using FBX it has an option to triangulate also. Don't give apps the chance to change your non-visible edges, define them so it doesn't have the chance to screw you over. There are probably other edges on your model that you don't notice but could screw up a reflection or cast a weird lighting glitch under specific conditions. Best to rebake with a triangulated mesh.

EVERY game engine triangulates meshes so it's not like you're hurting the model. What's important is that you don't triangulate it in a way that breaks your workflow, like defining one edge that doesn't really need to be defined, while leaving the others to chance