Methods for aligning high res sculpt to low res mesh?

Wondering how people have successfully aligned a high res sculpted mesh (e.g. Sub Division 5+ in Mudbox) to a low res mesh with different vert IDs and topology than the Sub Division 0 base mesh in Mudbox.

In Mudbox we’ve experimented with setting the Sub Division level to 0 for a sculpted mesh and then importing the low-res re-topologized mesh into Mudbox using Import Layer > UV Position (the UVs of the sculpt and the low res mesh are aligned). Sometimes it works and Sub Division 0 morphs to align with the imported low res mesh. But most of the time it gives an error saying something like “Imported mesh is not a Quadric Mesh” and the import fails. Any ideas on how to make Import Layer > UV Position actually work? I guess you aren’t technically aligning a high-res to low-res, since it’s set to Sub Div 0…

For some meshes, we were able to eliminate this error by taking the low res mesh into Maya and dividing it using Edit Mesh > Add Divisions > Quads. However, inevitably Mudbox gives the Quadric Mesh error again even with this divided mesh.

I’ve resorted to exporting the Sub Div 0 into Maya as an FBX where my retopped mesh is and then doing a Mesh > Transfer Attributes > Vertex Position On, Sample Space UV. I then export the aligned Sub Div 0 as an FBX out of Maya and Import as Layer > Vertex ID into Mudbox with the sculpt set to Sub Div 0. This allows the rough shape of the ReTop mesh to morph the sculpt. I then PageUp the divisions to 5, Import my ReTop FBX (which has different topology from the Sculpt Sub Div 0). Now I have my Sculpt overlaid and aligned with my ReTop and I can do a nice Normal Map Extraction onto the ReTop for use in-game.

This works well for aligning the Sub Div 0 to the ReTopped mesh because they have roughly the same number of verts. However, if I were to bring in Sub Div 5 to Maya and do Transfer Attributes, the Sub Div 5 wouldn’t smoothly interpolate its alignment with the ReTop mesh, it would actually morph into a blocky shape (picture the high res mesh shrink-wrapped to the low res). While I doubt there would be many cases where I’d need to morph a high res mesh to a low res, I’m still interested in finding a solution for that edge case…

You will probably have good luck at polycount. This seems like a question artists may be more used to solving- I think it comes up relatively infrequently so most of us haven’t had to script a solution to it :slight_smile:

The problem with your exisitng workflow is the alignment of Level 5 to Level 0: Maya will just align the Level 0 vertices and everything else is interpolate across the quad based on closest face normal to the original. You need to align Level 5 to Level 5. Maya can do it though I recommend you show nothing in the viewport to speed up the operation and select via the Outliner.

Have you tried Mudwalker? It’s meant to have some nice interoperability between Mudbox and Maya.