Hi Edoartworks,
Before diving in to the issues you’re seeing with vertex colors I want to address the reimport materials populating the details issue you noticed which has been fixed in 4.13.
This would happen anytime there was a reimport with any LODs. It did not have to be a specific version of FBX that was used. It had been around for quite some time too.
Now onto the Vertex Color issues.
“When I reimport it, the LOD0 is correct, but the other LODs are retaining the old vertex colors.”
This is true in the modeling program as well and is not a UE4 issue that I can see. When I create a mesh with 2 LODs and update the Vertex Colors only the selected LOD when the modifier in 3Ds Max for VertexPainting is added are affected not the entire mesh.
- Did vertex painting on the base mesh
- Created two lower LODs for the base mesh and grouped them in 3DS Max
- Selected the Group and applied a vertex painting modifier on the base mesh LOD
- Checked the lower LODs to see if it applied. It did not.
The gif here is switching between the LODs after having applied the vertex painting after the LODs have been setup.
I know this gif doesn’t necessarily show the detail of the settings here and whatnot, but the principal of it all is explained above with the setup.
Of course a workaround is importing a brand new mesh and replacing the old one, but this is not optimal in a big project.
It may not be immediately obvious but you’ll want to open the static mesh and in the details panel on the right you’ll locate the option for “Import Settings”. Then under the advanced rollout you’ll want to change the “Vertex Color Import Option” to Replace otherwise “Ignore” will be used by default and ignore any updates from the FBX file when reimported.
This should solve your issue, but it won’t with LODs unless you manually fix this in your FBX file.
-Tim
This will replace any previously imported vertex information with an update