Mirrored UV Baking Issues

atomander

Hey folks, posted this on my 3D thread, but thought I might get more specific help here. I am having two issues with my bake in Xnormal. The first:

1. I am trying to bake out half of a mirrored mesh, but am getting a seam down the center of the mirrored edge.



I have the UVs for the reflected section of the mesh moved to the right of the 0,1 UV space so that is doesn't interfere with the bake, and have adjusted the cage in Xnormal to encapsulate both meshes.






2. On the roller section, I am getting strange bake results on the cap of the cylinder. I've inserted an inner ring to try to help, but am still getting junky results on the caps of the gear teeth and the edges.



Any insight into either of these issues is much appreciated!

JedTheKrampus

What engine is the render in? If it's in Toolbag did you set the tangent space to Mikk for that mesh?

The problems on the roller are occurring because you didn't triangulate before you baked. Put a triangulate modifier on your modifier stack and export your lowpoly to Xnormal and your render engine and bake again, and those should go away.

atomander

Jed, throwing a triangulate modifier on both pieces fixed both problems! Thank you! Out of curiosity, why does having the mesh as tri's make a difference in the bake?

EarthQuake

For the second issue, as you can see little X shaped errors, the problem is that your mesh is being triangulated by your baker and your viewer differently. For any type of rendering, a quad always has to been converted to triangles, and of course a quad can always be split into triangles in two different ways. So depending on how your app decides to split the edge, the resulting triangulation may no longer match. So generally its best to triangulate before exporting, and sometimes baking depending on the app.

Certain apps like Maya actually change the mesh normals when you triangulate too, which as to be account for in some way, either triangulating before baking or locking normals before triangulating.

atomander

Thanks man! That makes sense now.

atomander

Ok, follow up bake question. Getting gnarly artifacts on the cross-section parts of the cover. Its a tricky area of geometry; the global extrude function in xNormal doesn't scale well for the interior cut out areas, requiring manual adjustment. Haven't yet found a good way to get a clean bake yet. Any insights on how to set it up better?