Hi guys,
Been on and off with houdini, but since the Houdini engine came out for Unreal Engine, I decided it's time to really get into this software (for destruction and procedural modelling and proc. tools for level design)

I am trying to import alembic into Unreal. I have this ball as a test, and I am not sure what am I doing wrong - the normals seem to be completely off when I import to Unreal. (image ball_1)

I followed different workflows, even the unreal engine stream, but one thing I noticed that is different - they have just one mesh in the import window. (Image ball_import)
I have multiple, in fact for every piece there is a mesh. Seemed ok for me at the start, but no one else has that.

Also I have a warning in Houdini that I am not sure what to do with. “Renaming node to *”. (Image ball_export)

I have tried using different options in the import window, for example recalculating the normals. But nothing seems to help. It almost seems that it import multiple meshes over one another, and the normal error is just polygons being over each other?

Notable node in the houdini network is a remesh with iterations set to 1.

Thank you!

Does the geometry have normals in houdini?

I suspect you are trying to export a collection of Packed Fragment primitives (or Packed Geometry primitives) for your object. This will result in a shape for each piece in the resulting Alembic archive. The warning is likely because you didn't specify a unique name for each piece so the Alembic ROP renamed some of the pieces. If you want a single object with deforming geometry, consider inserting an Unpack SOP before rop_alembic1.

The unexpected shading is likely a different issue. If you re-import the Alembic archive into Houdini, does the shading in the viewport match your expectations?

Thank you for this, that worked.
Also what I did before you guys answered, is that I exported with RBD to FBX node, after Luiz Kruel's tutorial - https://vimeo.com/200486901 [vimeo.com].
Seems to be much more stable!
But still have an issue with the normals. When I reimport back, the mesh seems ok? I am not completely sure on what the workflow is when it comes to houdini and normals. Do I set normals with the normal node right?
Thank you
Pavel

It's likely that the model does not have normals, and the auto-generated normals are cusped in the viewport but not cusped when unpacked in Engine. If you add a Normal SOP before you pack to fragments you should get the same result in both.

Regarding weird normals. Possibly scaling object up will fix it (if normals are already computed upstream). It's different from scaling directly in Unreal.

Ref from Reddit answer: https://www.reddit.com/r/unrealengine/comments/11q422h/comment/jc2650y/ [www.reddit.com]