Maya to Max - Internal Polygon Reriangulation

pasha_sevez

Few month ago I've faced a strange problem. When I create polygon geometry in Maya and export it to Max (OBJ or FBX) the hidden edges of the polygons become turned! It's making me mad - e.g. I simply can't export lowpoly to OBJ, bake normal in Xnormal and load it in Maya - the result will look incorrectly. While exporting geometry the smooth groups (hence, the face normals too!) change because of this strange force retriangulation. The worst consequence is that if I bake normal in Maya and transfer geometry to Max the result may look rather unpredictable.

Here is the shot if original geometry in Maya - pay attention on the hidden edges.



And here is the same model imported to Max



By the way - this retriangualation doesn't depend on the version of Max, Maya, FBX. Obj and Fbx result the same retriangulation. At the same time Softimage exports everything completely fine - both Obj and Fbx. Only exporting from MAYA causes this problem.

Can someone help me to solve this?

Piflik

Don't know how to solve this, but I'd like to mention, that the triangulation you have there in Max is perfect for the RT Display of Normal Maps in Max...hang on to it

Buzzy

In the import dialog in Max, there is an option to "Retriangulate Polygons" Make sure this option is disabled.

pasha_sevez

Buzzy wrote: »

In the import dialog in Max, there is an option to "Retriangulate Polygons" Make sure this option is disabled.

This option is surely disabled. As I already noticed the issue is presented in FBX as well - but fbx doent's have a retriangulation option.

Mark Dygert

What happens when you apply edit poly, go to Polygon mode and click re-triangulate? On a similar quad sphere I get something identical to what you have in maya.

pasha_sevez

Vig wrote: »

What happens when you apply edit poly, go to Polygon mode and click re-triangulate? On a similar quad sphere I get something identical to what you have in maya.

You are quite right but not completely. You've got the result which looks LIKE in MAYA because Maya uses Autoquad function - during modeling it dynamically changes the orientation of internal edges. When you retriangulate the mesh in Max the result LOOKS pretty similar but no identical because the retriangulation algorithms are mostly different.

Again - the problem is that It seems to be impossible to get model from Maya as it is in Maya. Neither retriangulation nor any other operations could help to do this for now.

Looking forward to you assistance, guys

Eric Chadwick

Triangulate before exporting. You won't have quads anymore, but you'll avoid this problem.

Mark Dygert

Oh what if you flip edges, I didn't know you could do that in Maya now, I thought it always re-triangulated everything, drove me nuts the last time I used it.

FBX doesn't like it when you flip edged in Max either, it complains and tells you its going to triangulate it how it does it. I always have to turn those edges visible like Eric pointed out for them to come out "correct". You could do like Eric suggests and triangulate the whole thing. You could then use Quadrify to turn it back into quads, it won't retrinagulate but only pick which edges are visible or hidden. Some times... it picks wrong and you have to make a few edges visible again, but in general it does a good job.

pasha_sevez

to Eric Chadwick:
Yes, I use this solution to keep correct triangulation, but it becomes a great headache to quadify 12-15000 tris model. Maintaining the mesh topology is important for rigging.

to Vig:
Maya 2010 couldn't operate on the hidden edges - there was a mel script on the creativecrash (ex highend3d) to make it possible. Maya 2011 gives such an "out of the box" option - it was even highlighted in its press release. But keeping in mind the export problem I find it (new feature) completely useless.

BTW when you export the polymesh (Edit Poly) from Max to FBX and the exporter reports on the inability to save diagonals orientation. In this case you don't have to explicitly triangulate your model (make invisible edges visible) - just apply Edit Mesh modifier and everything will export fine.

So still no solution for now But I'm still not down in the dumps )) There must be some way to export without a headache

thomasp

from what i remember the autodesk rep telling us about it is a feature in maya. seems the program likes to keep full control over all implied triangulation and changes it if it deems it necessary. seems this is intended for e.g. cloth simulation and the like.
it's just one of probably countless things that show maya was developed with film and pre-render applications in mind and games and low poly work didn't make it onto the agenda until many years later.

my last place ended up writing some custom import/export stuff to transfer geometry max<->maya while keeping triangulation and tweaked normals and - i think - was provided with customized FBX builds.
took a lot of pointing out visual artifacts to inhouse tech team and autodesk support and how a normal map needs to work on top of the vertex normals it was baked for to get that workflow...

without such help you'd be better off rigging a quad mesh with whatever screwed up triangulation your export process may give you and as soon as you got your deformations on, replace with a hand tweaked triangulated one and copy the vertex weights.

pasha_sevez

thomasp wrote: »

from what i remember the autodesk rep telling us about it is a feature in maya. seems the program likes to keep full control over all implied triangulation and changes it if it deems it necessary. seems this is intended for e.g. cloth simulation and the like.
it's just one of probably countless things that show maya was developed with film and pre-render applications in mind and games and low poly work didn't make it onto the agenda until many years later.

my last place ended up writing some custom import/export stuff to transfer geometry max<->maya while keeping triangulation and tweaked normals and - i think - was provided with customized FBX builds.
took a lot of pointing out visual artifacts to inhouse tech team and autodesk support and how a normal map needs to work on top of the vertex normals it was baked for to get that workflow...

without such help you'd be better off rigging a quad mesh with whatever screwed up triangulation your export process may give you and as soon as you got your deformations on, replace with a hand tweaked triangulated one and copy the vertex weights.

It seems to be the only solution - create lowpoly in Maya then transfer it to Max and unwrap/texturize in here. Thanks for your help, guys - it looks like I have to tweak my pipeline to avoid this problem. Maybe it would be really better to rig a quadded model with srewed triangulation and then transfer it to the explicitly triangulated one. Or use Softimage

beartraps

Sorry to bump this thread, but I've been having issues with this. I need to give a client a max file which they will then rig and export to Unreal as a skeletal mesh. Problem is that I work in Maya and these triangulation issues result in different display of normal maps depending on which program I export from. My solution has been to export a triangulated mesh from Maya into Max, use it as a guide to match triangles and flip each one manually by hand (tedious as fuck...)

In short, has anyone been able to find an easy fix for this?