Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.50
Broken: version: 2.83 (sub 13), branch: master, commit date: 2020-04-08 21:23, hash: rB1239cab11ff9
Short description of error
Paint Mask Selection wireframe is broken when the mesh is subdivided by either Subdivision or Multires modifiers:
Exact steps for others to reproduce the error
- Open file
- inspect broken Paint mask selection wireframe
- goes away if modifier (subd or multires) is disabled
When I opened up one of my files that I wanted to vertex paint, I noticed some really serious rendering artefacts that prevented me from seeing and painting the vertices. Here are images showing the issue. MultiRes/SubSurf and no modifiers create rendering problems on this model, but strangely enough I don't have these problems on every sculpt. I don't know yet the true cause of these bugs.
Here is a file with a piece of the model I had a problem with. Tried making it as small as possible.
To start finding the problem you first need to go into Vertex Paint Mode. The mesh should be all white with wireframes showing despite the option being toggled off in Viewport Overlays. Toggle Viewport Overlays settings on and off and try to change the settings and nothing works except when you disable Viewport Overlays completely.
If you start painting on the model (i.e. black) the paint will not appear on the model. If you enable MultiRes in the modifier window you will notice the broken rendering of the vertex paint with dark lines drawn all across the model.