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Pancho

Rop Alembic and Rop Output Driver only export 1k .abc files

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Something isn't working. Although the Rop Output Driver exports .obj, .abc export isn't working. It just writes 1k files. The .obj is about 200MB.

Output file is set to $HIP/filename_$F5.abc

Both Rop Alembic and Rop Output Driver fail to export a proper .abc

With the Rop Alembic I even get an error message:

Alembic exception: 0TypedArrayProperty::init()

ERROR: EXCEPTION

The export nodes are attached to the dopimport. I try to export an RBD simulation.

Anybody an idea?

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I had some buggy issues with ROP Alembic Output node... It sometimes exported UV, but sometimes it didn't(really randomly), or it won't save the whole frame range or something.

 

Test with just exporting one frame to see if it works.

 

What about using alembic export under File tab?

 

File -> Export -> Alembic

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You shouldn't be using $HIP/filename_$F5.abc in the Alembic rop, $HIP/filename.abc will do as Alembic files can store animation sequences in one file.

 

Another thing to check is that you have geometry on the first frame of your Alembic export, if you don't it will fail.  This may be your issue as some simulations don't solve on the first frame so there may be no output from your dopnet.

 

If you could post your scene it might be easier to debug.

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i've found problem with alembic regarding attributes, so also try turning off all the extra stuff in your rop so it only outputs as basic a dataset as possible.  then, start toggling on things once you've got it working.

 

also note that alembic reads in houdini tend to keep the abc file open and so re-writing an abc will either fail or cause problems for the session that has the abc already open (depending on your os).

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Thanks for all the tips. I'll try to delete all the attributes, in the meantime here's my test file. Maybe somebody sees my mistake instantly.

 

Tried to render only the frames from 2 - 240, but this didn't make a difference (in case there's no data on frame one).

 

Cheers

Tom

vdb_fracture_post_01_b_189.hiplc

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O.k., the last post concerning the attributes might be the solution.

 

I changed the order of the final nodes

 

Main tree > dopimport (to get the sim back) > unpack > delete all groups > delete all attributes > rop alembic output

 

Now it works, but it would be cool to know what's the reason the malefunction.

 

Like John mentioned, the $F5 isn't working in this case. Everything gets written into one file. How can I avoid that? The obj was 200mb. A sequence with 300 frames and I guess the windows file system will shut down or some other error is likely to happen. Is the rop output driver working differently?

 

Cheers

Tom

 

 

P.S.: Seems like the Rop Output Driver is exporting a sequence.

Edited by Pancho

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Looks like Cd as a point attribute is the bad guy. Can it be that simple?

P.S.: Alembic by itself: Is it only capable of handling one uv projection per object?

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is Cd just a point attrib or does it show up elsewhere as a different type of attribute (prim/vertex/detail)?  that's usually where i've hit trouble with alembic export.

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Ah, you are right! For the glue network I needed to promote Cd to primitive in order to delete the glue constraints! So, I guess the trouble starts with having the same attribute twice.

Just another thing:

Inside Houdini the whole sim takes about 20m. Exporting the sim took almost 5h!!! Each frame is 200MB, but this should be easily written to the HDD within 10s. Is Alembic so slow to export???

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i would write it out to disk first as bgeo, then re-import (and possibly use a cache sop) and write out your alembic from the bgeo's.  that way, you can try different settings on your alembic without having to re-sim.

 

are you writing to a network drive or local?  i'd try writing local and then copying it if it's a network drive.

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