How to work with a subdivided model in Substance Painter (subdivision surfaces)

[Billy Joe Williams]

Hello.

I am currently learning how to use Substance Painter.

I have a mesh in Cinema 4D that is subdivided. I took off the subdivision surface in order to bring the base mesh into Substance Painter thinking I would be able to subdivide it there because I would like to paint on it in its final state.

The model is appearing it its low res form in SP. How can I see it subdivided?

Thank you for your help.

Joe.

[Cyril Dellenbach]

Hi Joe,

Thanks for the question.

Unfortunately, you can't subdivide the mesh inside Substance 3D Painter. You'll have to export from C4D the mesh with the desired subdivision. 

With that being said, as long as the UVs are the same between your subdivisions, the textures made inside Substance Painter should work on all the subdivision's levels of the mesh.

Best regards,

[Billy Joe Williams]

Hi Cyril,

Thank you for the information.

So, in other words, the workflow would be:

- Make your UV Layout on the low-res mesh in C4D

- Drop the low-res mesh into a subdivision surface (at, let's say, level 3)

- Export the model from C4D with the subdivisions baked in

- Import the subdivided mesh into Substance Painter

- Do the texture painting on the subdivided mesh and generate the maps

- Back in C4D, apply the texture maps onto the unsubdivided, low-res mesh.

- Subdivide the mesh in C4D again and it will look right.

Did I get that right? Let me know.

Best,

Joe.

[Cyril Dellenbach]

I see no problem with that workflow, but I am not really sure why you would apply the textures on an unsubidivided mesh instead of the original mesh you used for Substance Painter.

Best regards,

[Billy Joe Williams]

Hi. The reason being that it is part of a character that is already rigged. Thus the points on the mesh are already weighted and the subdivision is added on top of it in order to smooth things out. If I were to switch to the high-res mesh, not only do I assume I would need to re-rig it, but it would be a lot harder to rig since there would be so many more vertices.

In my experience, sometimes you want to leave the subdivision live on a low res mesh. Do you know what I mean?

Joe.

[Cyril Dellenbach]

I'm clearly not an expert with animation, so I'll trust you on this one. Well, you shouldn't have any issue with the workflow mentionned above.

Have fun with Substance!

[Billy Joe Williams]

Thanks for your help. Having meshes subdivided in realtime in a 3D program is very common, especially in character animation. I suppose I will try at some point and see what happens, however I wish someone would have a definitive answer. Would you be able to perhaps ask your supervisor and see if they could find out how character animators handle this issue. By the way, I often write articles about 3D software and vfx and was planning to do something about Substance Painter. This information will be very helpful to me if I could find out the recommended workflow when dealing with this case. Cheers,

[Cyril Dellenbach]

Don't worry, I can definitely tell you there are no problems with the workflow mentionned above. Substance 3D Painter will simply export your work as 2D bitmaps. Therefore, as long as the UV islands are the same between the subdivisions (and it should), the textures will look the same on the first and the last subdivision.

The most common workflow is simply to have a Low Poly model and to bake it with a High Poly model. Choosing which subdivision should be your Low Poly is on you.

Now, like most artists on the team, I'm a texture artist and if you wish to have all the tips and tricks of 3D animators, you'll have to look for one. 

Good luck with your work and best regards,

[Billy Joe Williams]

Thank you.

[Colorbleed]

@Cyril Dellenbachjust wondering - is there any chance Substance team might consider allowing to subdivide the model on import? Not necessarily dynamically, but say in "project settings" for the workfile, so that e.g. an input model could be subdivided a few times (potentially between `catclark`, `opensubdiv` etc.) but likely adaptive opensubdiv would influence the painting engine quite a bit. Anyway, subdividing on file open shouldn't touch that too much because it'll draw on that subdiv continuously?

It's a bit of an annoyance pipeline wise that our base models usually need prior subdividing to use as a decent visual ref in Substance Painter. It basically means we need an additional output file amongst our generated outputs.

[Colorbleed]

Actually, funny thing! If you use a .usd file to load into Substance Painter, then suddenly you DO get access to subdivide the meshes on import.

There is unfortunately an issue that it 'smoothes' the UV sets as well and thus the painted map don't seem to align with the smoothing that most renderers appear to use for UVs at rendertime (when subdividing e.g. same mesh at rendertime in e.g. Maya or Houdini when rendering with both Redshift or Arnold).

@Cyril Dellenbachwhich leaves me curious, would it be possible to also expose a "UV smoothing" method (like most DCCs offer)? Or what's the reason e.g. that when importing a Cube as USD and enabling the subdivisions that it also 'smoothes out' the edges of the UV set. I don't see the same thing occur with renderers like Redshift or Arnold.

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Also, bonus points for being able to "author" the material sets of the USD file inside Substance Painter as well so that e.g. the separate texture sets someone might want available on a model that's brought in does not need to be predefined. For now we can use a pipeline pre-load step where we use an intermediate USD file sublayering the original geometry but only adding material binding opinions so Substance Painter loads it like that instead. (However, would prefer to avoid the need for that Intermediate Step)