Getting UVs and colors to work with dynamic mesh using FDynamicMesh3

Development World Creation
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1

I’ve been working with FDynamicMesh3 for a while now but have just recently got around to working closely with the UVs and colors of the mesh I’ve created. My issue is that no matter what I do, I can’t get the UVs or colors to work. (As I understand it, the color problem should sort itself out if I can solve the UV problem.)

The mesh I’ve created is a flat (2D) circle. Sample: grey tiles are my mesh. I’ve verified that the UV and color buffers in the FDynamicMesh3 object contain the expected values alongside the normal data, but the only indication I have that anything is working is that it’s getting the vertices and triangle data and generating the mesh, but it’s not doing anything with the UV/color/normals.

I read recently someone had managed to get everything to work by using some functions from the FDynamicMeshAttributeSet family (CopyVertexUVsToOverlay and CopyVertexNormalsToOverlay) , but I’ve had no such success. I wrapped the FDynamicMesh3 in a DynamicMeshAttributeSet and tried the functions indicated and there was no change.

If I drag the actor class with my mesh generating code into the editor viewport and use the Modelling mode → AutoUV setting, it takes a few seconds to think and then the checkerboard pattern tells me that the UVs are set and working (but still won’t show my colors).

The only things I can say about my situation that are objectively true:

  • The FDynamicMesh3 data is being successfully placed in the container
  • The vertex and triangle data is being used successfully to render the basic mesh
  • Vertex and triangle data was working both when I was only using FDynamicMesh3, and also since I wrapped it in the FDynamicMeshAttributeSet object.
  • Nothing I have tried programatically, including the recommended functions, has ever worked to produce the outcome I’m expecting (mesh covered in a kaleidoscope of colors).

I need a way to get them to work programatically and would love if any of you have managed to get this to work and could drop a tip or two.

Thanks very much in advance.

2

After some digging around, this post what ended up solving it for me:

I am doing these (not sure if all of them are necessary)

	FDynamicMesh3 newMesh;
	newMesh.EnableAttributes();
	newMesh.EnableVertexUVs(FVector2f::Zero());
 
// generate vertices with UV logics ....

	UE::Geometry::CopyVertexUVsToOverlay(newMesh, *newMesh.Attributes()->PrimaryUV());

Voila!

3

Hey, thanks for your post! Sorry it took so long to respond. I have a few other things to test before I can try your solution but if it works I’ll make sure to come back and mark it properly.

Thanks again!