Author Topic: Why Export with Smoothing Group enabled?  (Read 2619 times)

Hi,

I saw a few Wes' tutorials and he always use "Smoothing Group" on Maya Export, for both low and high poly models.

While that's all nice, I wonder why? Because I tried exporting without this option enabled and SP still seem to bake just fine.

I can see in the FBX file (using ASCII mode), "Smoothing Group" option adds a set of Smoothing data, but what good does it do for SP? Isn't it just a 3ds Max thing?

David

Based on the lack of replies, I guess the answer is "SP doesn't depend on it, we just happen to export both hard edges and smoothing groups as a precaution?"

Based on the lack of replies, I guess the answer is "SP doesn't depend on it, we just happen to export both hard edges and smoothing groups as a precaution?"

Hi,
I'm very sorry for the delayed response on our forums. I posted there as well.

Substance Painter will read the soften/harden data set in Maya when you export as FBX. This data is used to shade the mesh in the Painter viewport similar to maya based on vertex normal smoothing. In maya you are smoothing/hardening the vertex normals. Smoothing Groups are used in FBX file format and it's useful to have it enabled for other software that supports it such as 3ds Max. However, this option is not directly used by Painter if you export from Maya. It doesn't cause a problem to have it enabled if you are using the same fbx in Painter and then again in other applications.

I am also getting the issue where Maya 2018 reports triangulation and Smoothing Groups is not supported. I'm not sure what's going on there as it works in 2017. Also, with Painter we currently support FBX version up to 2017.

In your example above, you have a hard edge low poly cube and bake a high res mesh of the cube that is smoothed. You can get a similar result as if you baked the low poly cube as fully smoothed. This is because in the Substance Painter baker we have an option to use Average Normals for the baking. This produces a similar result if you had Averaged Normals disabled and then baked the low res mesh with smoothing. However, with hard edges if you don't have a UV split that corresponds to the smoothing split, then you will get seams as you can see in the hard edge cube example.

Please let me now if that doesn't make sense and I'm very sorry for the confusion in the video. I should have left the smoothing group part out when discussing the FBX export options since I was using Maya  : ) 

Cheers,
Wes
Head of Substance Demo Art Team
the3dninja@adobe.com
Twitter: The3DNinja