
I have no idea why this works but it seems to magically allow Painter to read the normals properly.

The only thing I have tried to fix this successfully was a tip I found in an old reddit post when googling the issue: importing my fbx into Blender and then just re-exporting it from Blender. Often after doing one of these troubleshoots, I then get additional error messages in Substance saying that my tangents / bi-normals are invalid, as well.

and then re-calculates the normals itself. "Mesh normals are invalid (some values are null) and will be recomputed" I'm encountering an issue I can't seem to find any documentation or posts about: when I import certain meshes into Painter, it tells me: Hello! I'm experienced with Maya and other 3d programs but am fairly new to using Substance Painter.
