[URP] Geometry is generated in a way that causes NaN issues for shaders with normal maps.

[naelstrof]

Steps to reproduce:

1. Use a URP project
2. Enable bloom in a post process volume
3. Apply a surface shader that has a normal map to a real-time CSG surface.

We've confirmed that realtime CSG was the problem by exporting the mesh to blender-- Merged close verts and cleared split normal data, then reimporting.

This even happens with the built-in shader with a normal map placed in the normal map slot.

[nukeandbeans]

There has been a community fix provided with #372, but the developer is still working on it.

[XgarhontX]

I wrote a script for my game to delete the NaN faces (they all have an area of 0) https://github.com/XgarhontX/Delete0AreaFaces. It needs to ProBuilderize the RealtimeCSG mesh first, so someone can improve it by making RealtimeCSG do it itself.