Strange Checkerboard Patterning from Decimation

[Kazi]

I have a 3D scan of an article of clothing that I refined and sculpted on in Zbrush. My workflow typically consists of using zremesher to produce better topology than what comes out of the scanning software, and subdividing + reprojecting detail to return to the original resolution.

Sometimes my clients will request a triangle-only mesh. As you know, Zremesher works in quads, so I usually decimate the model to 99% to produce a triangle mesh of practically identical resolution. However recently I have been getting this strange patterning on the mesh when triangulating the mesh, which is visually negligible for the most part but it still concerns me from an optimization point of view. I would rather learn how to prevent this from happening rather than ignoring it and allowing it to persist.

Now the strange thing is that alternative methods of triangulation, like importing the model into and then immediately re-exporting from a software that automatically triangulates quads, also produces the same issue! So i’m not even sure it is a Zbrush-specific problem, but since Zbrush is where I am starting from I decided to ask on this forum.

Thanks in advance.

[tobor8man]

FWIW … the four verts on each pair of tris that form each quad look like they form a tetrahedron, each vert pair in a different plane (for example the upper and lower opposing diagonal vert pairs on a cube). Suggests to me that perhaps the refined mesh is so small that when projecting it’s picking up the highs and lows of the fabric weave/knit. If you’re not looking for that level of detail then subdivide for the smoothness of folds but stop projecting the scanned mesh details at the higher levels.