UV copy bug

Toglik

Hello Polycount community.

I am facing a frustrating problem that I don't know how to solve. I am trying to copy my UV from a mesh to another, but visual artifacts shows up when I do so. The 2 meshes are exactly the same, same number of vertices, faces and edges, vertices have the same numbers from a mesh to another. And yet, It seems like I can't copy UVs from a mesh to another.

Here is what it looks like with Screenshots. My first mesh is the T-pose mesh with the correct UV layout. The UVs looks clean :

On the second mesh, it's the pose I made in Zbrush. Once again, the mesh are the same, same topology, same vertices numbers etc, just the pose is different. When I copy the UVs from the T-pose to the posed mesh, it looks like that :

Notice how the UV layout looks exactly the same, but seams are visible on the 3D mesh that are not visible on the UV layout.

It gets worse when I try to apply the textures on Marmoset for example : on the T-pose, textures looks great :

But on the posed mesh :

I am speculating that is the same issue. If anyone has the answer to this it would be awesome and save me a great amount of time. I tried everything, deleting the UV, reset Xform, reapplying the UVs... I always end up with the same issue. In the past (on older version of 3ds max) I used this technique to copy/paste UVs without any problems.

I am using 3DS max 2018 right now.

I did the textures in Substance Painter, I don't think it's really important but maybe worth mentionning.

poopipe

Zbrush has most likely screwed your normals and thus tangents/binormals .
Try using an edit normals modifier to reset them and then set up any smoothing groups you need. 

Eric Chadwick

Also the exporter and/or importer may have introduced differing triangulations between the softwares. 

Toglik

I tried to fix the normals insde 3DS with "edit normals" modifier but it doesn't work. I tried reimporting my posed mesh and unchecking "Retriangulate Polygons" in the OBJ imports options, but it just changed the seams from my original mesh. So the problem remains.

Inside Zbrush is there options for exporting ? I just use the "Export" button on the Tools palette, but no pop-up window open to ask me for options.

Eric Chadwick

Try adding a Morpher modifier to the original mesh, choose the posed mesh as a morph target, then set it to 100%. Might work.

Toglik

Dude you're a genius, I didn't think about that but it's totally working. Best way to solve an issue sometimes is to counter it ah ah.

Well, if someone has the answer to my original problem, I am still interested