Importing Maya to 3DS MAx causing vertex normal issues

Mambo4 · Jun 2013

My studio uses 3DS Max. Our outsourcer has been working in Maya and importing to Max for delivery. Our Studio pipeline uses Max > FBX > custom engine.

The problem is often the models come back looking fine in 3DS Max, but having broken vertex normals after exporting as FBX and converting to the game engine. There are generally 2 kinds of errors:

1.) the vertex normals are broken. the fix is to add an "Edit Poly" modifier to the model in Max (breaking the normals) and then reassign smoothing groups.

2.) specific to mirrored UVs: fixed if you duplicate and mirror the geometry.

I am investigating with the outsourcer to determine the intermediate format. (Maya > FBX > 3DSMAX or Maya > OBJ > 3DSMAX)

I know this sort of thing has been discussed before (at least issues #1) , but a quick google wasn't yielding any threads of use.

Ideally we can isolate the causes get the assets fixed without any post editing in Max.

Does anybody have some advice for smoothly going from Maya to 3DS Max while avoiding vertex normal issues?

Eric Chadwick · Jun 2013

Have you made sure the studio and outsourcer are both using the same FBX version?
http://download.autodesk.com/us/fbx/20112/FBX_SDK_HELP/index.html?url=WS1a9193826455f5ff-e569a012180ce5891-1ecf.htm,topicNumber=d0e3725

Different versions deal with things differently. Also make sure the same export options are used by all.

frobbins · Jan 2015

Howdy.

I see this thread is old but, I thought I'd revive it. I am having the same issue however, I work in Maya and I need to import my meshes into Max (our tools are limited to exporting game meshes from Max only). It seems the problem is Max has independent smoothing control through vertex normals and smoothing groups and Maya simply relies on vertex normals. Is there some file translation script or plugin that can do a better job of normal/smoothing group conversion? Is there some process I can go through to get my meshes to import normal/smoothing group info properly?

Thanks!

c.buliarca · Jan 2015

I am using fbx to export meshes with soft and hard edges, and with the smoothing groups option checked for the fbx plugin when exporting, and it's doing a good job in converting the normals to smothing groups in Max. But I remeber that if you had a mesh in maya that used the average normals technique and not the soft/hard edges the mesh in Max didn't came properly. If you have using that you can easly use a script I've done to convert your locked normals to soft/hard edges so you can export it.

http://buliarcatools.blog.fc2.com/blog-entry-1.html

Todd Dinosaur · Nov 2023

Hello! It's been 10 years but here is the solution:
In 3DS Max, in the FBX import dialog box, UNCHECK the "smoothing groups" box.

Logic seems that you would want to CHECK the box, but don't.
This seems to be the solution for whatever version of .FBX you use too.
Enjoy!

Image: https://us.v-cdn.net/5021068/uploads/editor/yn/j1drx5fqozko.jpg

poopipe · Dec 2023

That depends on how the file was exported - Maya is capable of exporting valid smoothing groups to fbx (it's a feature of the fbx format, not to be confused with max smoothing groups) and they can come through to max correctly

Regardless though, on import you'll end up with explicit normals on the imported mesh. Any further mesh edits will require that you reconstruct the normals so you might as well assume that you're going to need to rebuild them in your primary DCC

Importing Maya to 3DS MAx causing vertex normal issues

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