Mirror and weld modeling workflow with baking?

DirtyBlueFL

Hello friends and associates, I am working on a sword for a VR game mod, and I've opted to mirror and weld one half of the sword so I can maximize pixel density in the materials. This is the first time i've ever made an asset with baking where I didn't just lay out everything in the UVs with no overlapping. So of course, I've run into some questions (problems) along the way.

My workflow was as follows in Maya 2017:
>Build the full high poly, both left and right, using subdiv smoothing. Multiple submeshes were used, but this didn't cause any problems.
>Retopo one half using Live Surface and Quad Draw tools, as one contiguous mesh.
>Create smoothing groups by selecting edges and setting them to hard or soft
>Unwrap
>Bake normals and AO using the low poly half and its cage, on the full high poly mesh
>take that half, with baked maps, and texture it in Quixel

At this point, I stopped to check my theory on how I'm going to execute the mirror and welding, and ran into some problems.

When I mirror and combined the mesh (no merge/weld) sometimes smoothing groups break.

Why? Is this just a problem with Maya? I have to go in by hand and fix edges.

When I mirror, combined, and merge/weld, smoothing groups always break.

Why? Is this just a problem with Maya? I have to go in by hand and fix edges.

When I soften the new edge down the center, I get a harsh seam down the middle.

Is this because the half-bake considers the outer edge as a hard edge, and by softening the new center line, I am essentially giving the low poly smoothing data that does not match the bake?

When I mirror, merge, and don't soften that edge, things look great, other than the broken smoothing I fix by hand.

Should I go into the UVs and split the islands outer seams? When I merged, the UV verts also merged. I have player around with mirrored geometry assets from AAA games, and their UVs were overlapping and mirrored, but NOT sewn together. Am I missing a step?

Can you point me to workflow guides? The way I'm working now is just my interpretation of what I think I know about the process. Is Maya maya at fault for the broken smoothing, or am I just overlooking a setting?

Broken smoothing groups in the low poly


Mirrored, welded, hard edge down the middle


Mirrored, welded, soft edge down the middle



Some renders

Millenia

I'd weld it, soften the edge and offset the mirrored UVs by one unit so that they don't contribute to the projection but still occupy the same space in the texture.

DirtyBlueFL

So I'll need to split the UV islands along the newly welded edges. If I move those inverted UVs over to 0:0 or w/e other UV square I so choose, how will those not be contributing while also picking up the material and showing their correct materials? I may be not understanding what's exactly going on when moving UV shells to a space other than 1:1

Millenia

Basically, anything that's not inside the main square still takes up the same UV space but since it's outside of the square it doesn't get used for projection.

Eric Chadwick

We have some more about this workflow here on our wiki
http://wiki.polycount.com/wiki/Texture_Baking

DirtyBlueFL

Fixing edges which break on a case by case basis, and leaving the merged edgeloop as a hard edge, provided a smooth gradient when the baked normals were applied.  Here's what I've got after some NDO work.

DirtyBlueFL

finished!