I'm trying to export an alembic file in Houdini to import in Maya.
But when i want to import it, my maya is not responding.
I think it is because of all the warning nodes in my ROP Alembic Output node.
Warning: Renaming node to /ALEMBIC/file2_1 to resolve collision.
This and for 998 other files (file2_2, file2_3…).

greetz Kobe

The warnings indicate the Alembic ROP needed to move items in the hierarchy – it should not prevent geometry from being exported. You can verify this by trying to re-import the geometry into Houdini. You can also use the “abcecho” command line tool to inspect the contents of the resulting Alembic archive.

Can someone please eloborate this.

Alembic archives store data in a hierarchy. The Alembic ROP needs to express the data being exported as a hierarchy in the Alembic archive. In koberoels' scene, there appears to be an Object (/obj/ALEMBIC) containing a File SOP (/obj/ALEMBIC/file2).

When koberoels tried to export the scene with the Alembic ROP, it was told to create a transform node (/ALEMBIC) and a shape node (/ALEMBIC/file2). However, when the Alembic ROP converted the geometry into a form suitable for Alembic, it discovered the geometry requires multiple shape nodes (perhaps it contains a bunch of packed primitives, or a mix of polygons and NURBS surfaces). Only one shape node ended up being called /ALEMBIC/file2. The rest were named /ALEMBIC/file2_1, /ALEMBIC/file2_2, etc.

Hey @koberoels

I got this error too and found that if your geometry is packed in the scene alembics don't like it. Put an unpack sop before your ROP Alembic and there won't be errors. It will also export much faster! While you're there, put down an attribute delete sop too and * the attribute fields to delete all extra attributes for a cleaner export.

Best,
Elizabeth

I am hitting this wall as well but can't seem to make it work by just putting an unpack SOP before the Alembic Rop.

I have exported Alembics from Houdini to Maya many times before but never with a Fracture node creating a ton of smaller bits.

I was thinking about baking a Redshift Proxy but then would need to next the shaders in correctly before sending it back to Maya.
So I was still just wanting to solve this on the Houdini side so I could get it into maya somehow.

Wanted to chime in that I was able to get Alembic to work witha RBD fracture setup out of Houdini to Maya.

Using the Convert node to first convert "all" to "polygon soup" before the file cache was one method of clearing out other data
that seemed to be making the Alembic file wonky and end up loading into Maya very slowly as it raises ram and then crashes eventually.

BUT... even though I did do this convert, I added another one post the file cache between the FileCache and Rop Alembic output using "mesh" to "polygon soup"

This made my very large 170-GB almebic animation of exploding rocks load into Maya very quickly. None of the sitting there waiting for it to load forever was happening. Just enough time to load the geometry into the GPU which was about 15 seconds on an i9 with 32gb ram and a 3070 card.

It plays decently fast and I could make a 550 frame playblast with it in under a minute to test it.

I will add that I was not able to get the alembic to load into Maya 2020.4 without crashing no matter what I did but through a process of elimination (trying everything/options etc one at a time) I did find it would import into Maya 2019 quite well.

I now have to try getting the motion blur to work by adding the promote attribute node and getting Cd/vector data into the Alembic successfully to see that Motion blur is working.

Screencap showing the complexity of the alembic I was creating. It does not have the Convert nodes in the graph yet.