Modifying ProBuilder geometry when using bloom post-processing creating flashes

Unity Engine
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1

Unity 6000.0.3f1 / URP
Probuilder 6.0.1

I recently enabled bloom post processing in my game and what I’m experiencing is bright flashes occuring as I move the camera when a probuilder mesh that’s had some kind of deformation on it is in the scene. So for example I can add a probuilder cube and it’s fine, if I then edit a face and shift+scale then shift+translate to make a hole in the middle now that object has a sparkly flashing effect on it.

Changing the material on the probuilder mesh does not fix things. The only thing which fixes things is enabling “Stop NaNs” on the camera. This however leaves the flashing occurring in the editor which makes it very annoying to work with. Am I overlooking something simple? Video of the effect follows.

2

I’ll add I just recreated this in a new project.

  • Create a new URP project
  • Install ProBuilder
  • Add a Probuilder cube
  • Use face edit mode to shift+scale a face

That seems to be enough to cause the issue.

Edit: Issue occurs in Unity6 using older Probuilder (5.2.0), does not occur on 2022.3.24f on the same version of probuilder.

3

Unity 6000.0.27f1, ProBuilder 6.
The problem still remains.

4

Unity 6000.0.34f1 - Issue still prevalent.

5

Same issue, Unity 6000.0.42f1 - Probuilder 6.0.5

6

the underlying issue appears to be a combination of some bad behavior on probuilder’s end, combined with some changes to unity’s GI code.

while editing a probuilder mesh, if two vertices have the same position, probuilder can’t calculate the normals correctly - so it sets the vertex normal to 0, 0, 0.

it used to be that unity’s GI code was hardened against normals of 0, 0, 0 - but that doesn’t appear to be the case anymore. you can fix the issue for pixel shaders by modifying a line inside the core render pipelines package, if you’re comfortable with that.

the file is under the path com.unity.render-pipelines.core/ShaderLibrary/AmbientProbe.hlsl. modify line 66 to:

return max(real3(0, 0, 0), res);

1 Like
7

This fixed the issue! Thanks so much