Hi, I'm importing a mesh with UV's from Maya, shattering it and simulating it in Houdini, as well as adding new UV's for the inside prims, and re-exporting it as an Alembic to be lit and rendered in Maya. All went well until there was an update in the modelling UV's and I had to pass it through the setup again. Now, when importing the Alembic back to Maya, I get:

// Warning: normal vector scope does not match size of data, skipping normals //
// Warning: UV set sample size is: 2343643 expecting: 823070 or 2343630 //

And the model doesn't have UV's anymore. I tried several different things, the most promising of which was to use a polydoctor, it worked on one frame but when importing the whole sequence, Maya crashes. I went through this thread [forums.odforce.net] but most of the solutions either didn't work or implied making changes to the simulation that is already approved. Anybody encountered that and has an idea how to fix it?

Hi there, your issue seems hip file specific, so I'd probably need that to see where the issue arises. If you do post it, lock any imported files in the scene so we can check them out. You said you used a polydoctor in Houdini, which can clean up geometry, but I don't think it would resolve your UV problem. As long as they are inherited before the sim, they should transfer correctly. Also test with a partial alembic write, so you don't need to wait for the entire write to do iterations.

Thanks Midassilver, I ended up exporting .ass files instead of Alembic, since it rendered correctly in HtoA. The Polydoctor actually solved the problem when exporting a single frame, but the Alembic of the whole sequence crashed Maya. I'm thinking it might be a problem with Maya's Alembic importer, since re-importing the Alembic in Houdini worked perfectly.

Well if your uvs get broken in the sim, but exist properly at frame 1, then that explains why the polydoctor might fix the uvs at frame 1, but not for the rest of the sim. If you are up for it, post the scene, and we can check it out.

Sorry, can't really do it! At least it rendered correctly with the .ass files. Wish I knew what the problem was though.

If its a scene file permissions thing, I can understand that. Instead, try and replicate the problem in a simple test scene and see if it happens there. If it does, then perhaps you can share that scene here instead.

Sorry Midassilver, a simpler geometry did not result in the same problem.

However, if anybody encounters the same issue, I was able to fix it after all, using a vertex split SOP and promoting UV and normals to point attributes. Works perfectly now.

Hi everybody. I was having the same issue and none of the suggested solutions worked for me. What DID work was to change Detriangulate to "No Polygons" on my boolean fracture node. Hope that can help somebody in the future!

I am at this step now as well.

Fractured an object using RBDMaterialFracture >ran object through UV process before it gets to RBDConfigure>RBDBulletSolver>FileCache

So now I have this pretty nice sim in FileCache that refreshes decently quick in Houdini but every attempt to get it back into Maya crashes Maya on import. Like... it doesn't kill Maya but rather freezes it up indefinitely.

I did successfully get a sim out of an earlier iteration of this using the convert node before the alembic ROP but that takes a very long time. About 13 hours to convert the whole sequence. Using Convert All Types to Polygon.

But for some reason this new iteration isn't successful in creating an Alembic that Maya can import. The Earlier iteration that worked didn't have UVs for the inner pieces and this version does. I can read the UVs if I preview the convert node after the File Cache. So they are transferring across the node network. Just need a way to make an Alembic that is usable in Maya.

Switched convert node to From Type "All Types" and Convert To "Polygon Soup" and the alembic successfully makes it into Maya.
Scrubs pretty nicely as well. BUT... no UVs

I can still see them at the Convert node and the other nodes to test. But just ran from Convert to Alembic Rop to try and get it out to Maya. So It does make it to Maya but no UVs. Any idea how to force the UV attribute into the Alembic file?

Load the abc in Bifrost and it will work just fine. No need to promote anything either, Bifrost can read all pts, vertex, and prim attributes.