I have an very simple animated mesh that has uv values per vertex. My point count does change per frame.

When I export a single frame the uvs get exported fine. When I try to export a range of frames the uvs don't export - just the geometry.

Is this a limitation of the fbx exporter/format?

Thanks for any ideas
Steve

houdini 9.5.241

Hi Steve,

While “uvs for geometry with variable number of vertices” isn't a direct limitation of FBX format, it stems from the other, more general limitation of not (officially) being able to convert geometry with variable number of vertices at all.

While we found a way to actually do it, we still have to go through FBX mechanisms meant for constant vertex-count objects. This means several limitations, one of which is the loss of most of the attributes on the objects.

I've re-checked our code again, and unfortunately there isn't anything we can really do on our part at this point. Several months ago I've logged a request to the FBX team that “real” variable-vertex count geometry support would be a key feature for us, but they didn't say anything definitive in response.

Would an OBJ sequence be an acceptable substitute for you in this case?

Oleg

Actually yes I just checked and I can get an obj sequence to work. Actually the added benefit is that the geometry which was quads maintains itself as obj. The FBX solution triangulated and split vertexes, and unfortunately merging the vertices in maya was not a viable solution due the size of the mesh.

As an aside - is there a trick to getting the fbx export to maintain quads going into maya?

Many thanks

Steve

As an aside - is there a trick to getting the fbx export to maintain quads going into maya?

The exporter will maintain the quads if your animated object has constant vertex count - there is nothing special that needs to be done in that case. For objects with variable vertex counts, though, there's unfortunately nothing we can do - this is part of a workaround for FBX's inability to properly support these kinds of meshes. Without triangulation it wouldn't work at all.