What's the most non-destructive means of exporting .abc's from Maya into Houdini so that a fluctuating hierarchy and tentative naming on the Maya side will only do minimal damage to the work done on the Houdini side.

For example,
Say I create an alembic archive with ‘Using Subnetworks’ off and assign a material using a material SOP within one of my shape nodes. Back in Maya I add a null above that shape's transform and re-export. If I hit “Build Or Update Hierarchy” back on the alembic archive it adds that new null as an alembic Xform node but If I peak inside where I planted my material SOP, it's missing. If I take that same shape and add the material at the object level, it also disappears.

I understand that materials should ideally not be assigned until the hierarchy is finalized but is there any other means of editing the contents of an alembic archive and be confident that the next update won't erase all of the edits you may have done?

Nobody uses the alembic hierarchy node for anything but debugging. Using it in production would result in redoing all work inside whenever there are changes upstream. Even adding a single node requires rebuilding the entire hierarchy and losing all changes within.

The preferred way of working with alembics is purely sop-based. There a path attribute exits to indicate hierarchy locations and material assignments can be made using path attribute masks as groups. This method would allow additions and subtractions to the archive without much pain. Renaming or inserting a transform into the hierarchy would cause some mild problems, but can probably be fixed quickly with find and replace.

Thanks for the reply! That makes a lot of sense.

Is it possible to give me an example of what your workflow might be as far as extracting the different groups/shapes at the sop level and your settings on the alembic sop. Blast nodes? Splits? All in one stream?

Do you work packed or unpacked?

If you’re calculating velocity vectors would you then just merge all of the streams together and drop a trail sop?

Any insight on to some of the finer details is greatly appreciated.

Cheers!