Curious on how people "merge" different Alembic files?

[corban]

Trying to see how others are approaching (if they are at all) the concept of "merging" two alembic files into one?  We are looking to take an original abc file and updating it with a newer parts from another alembic file.  

For example if we have a character asset in a single abc file with clothing, and the clothing is split out for some finaling fixes in say houdini or maya.  We then write that abc file back out to disk and what to take the original character file and replace the old shirt with the new shirt in the new abc file.

I know you can do this kind of merge in apps like Katana and houdini but we were just wondering if anyone was doing this outside an application with files on disk.

thanks

corban

[Andrew Harvey]

I haven't tried doing this myself, but is this something the new
Alembic Python bindings may be suitable for?

- Andrew

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[Ben Houston]

Exocortex Crate has a set of command line tools for various merging
and filtering of Alembic files. :-)
-ben

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Best regards,
Ben Houston
CTO, Exocortex Technologies, Inc.
http://www.exocortex.com

[Rob Bredow]

For example if we have a character asset in a single abc file with clothing, and the clothing is split out for some finaling fixes in say houdini or maya.  We then write that abc file back out to disk and what to take the original character file and replace the old shirt with the new shirt in the new abc file.

My preferred workflow for this is to put the character in one Alembic file and the clothing in another allowing the cloth-only file to be versioned up separate from the character's skin. Then, with your lighting system you can always know to load both the character and it's cloth at render time.

Alternatively, if you wanted to avoid a post-merge you could make sure to read both the character and the cloth into Houdini or Maya for your finaling fixes and write both out together when completed.

Rob

[corban]

Hey Rob,

Thanks for the reply.  This approach is similar to how we work today.  The problem is if the skin also has to be worked on.  How can one merge back in the "teeth" that are also part of the skin.abc file?  We are trying not to go back to splitting everything into smaller sub assets.  

I like the idea of a single abc file as it's easier to version.  You know that everything in the single file is meant to match.  When separating out the skin and the cloth into separate files lighters tend to ask the question: "Do I have the right version of these separate files?"  We run into this a lot.  

I like the Houdini idea and currently have it up and running trying the same approach.  Artists works with one version then at "render" time artist merges orig.abc and modified.abc into new_orig.abc.  Post finaling wrapper scritp.

Thanks!

corban

[Jonathan Gibbs]

Our artists don't like bringing in the whole character asset, and they don't like to plan in advance which bits of the character they will touch. So, their current pipeline has them:

1. importing portions of the character in tools like Maya
2. modifying those surfaces
3. exporting only the changed surfaces
4. merging the changes into a new version of the character model

It is nice that they pass on an entire (validated) character model and no one has to worry about what bits they changed.

--jono

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