Quote from Magnus on 17. December 2018, 13:15

As far as my research go what I found is that geo and bgeo is more optimized in houidini than alembic, which makes sense as it is the native format.

I was trying to export a geometry selection set with one of the rigs, but without any great success. Could you point me in the right direction on how you would do that with Prism?
https://app.hyfy.io/v/abK2udfCMsn/

Also, I also noticed that Alembic doesn't add the visibility channel in the export, so all geometry is visible all the time which is no good. I guess with the mGeo exporter the visibility could be added as a custom attribute, but do you know if it is possible to make that work with alembic?

EDIT: I found this on autodesk documentation pages:

Write Visibility
Turn on to store the visibility state of objects in the Alembic file. Otherwise, all objects are considered visible.

https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/Maya/files/Alembic-Export-htm.html

EDIT 2:
Found this article:
http://mrkunz.com/blog/12-08-2016_Export-Alembic-geomtery-from-Houdini-utilizing-the-visibility-property.htmlT
It describes getting visibility from houdini to Maya, but I geuss it could work the other way around? I twould be super awesome if the prism alembic export could somehow automate this, if it is not too complex.

Quote from Magnus on 17. December 2018, 14:23

by the way, I've heard good things about 'Exocortex:Crate' which is as far as I understand offer more export options for Alembic, for example 'Material Metadata'. I think it is free, and it is widely used in many studios.(EDIT: it is not free actually.... bummer) Maybe this would be more interesting for you as it opens up more possibilities than just maya to houdini.
http://exocortex.com/products/crate/description

EDIT: since it is not free I guess it is not relevant, but I'll just keep the post here in case it could be useful for anyone

Quote from RichardF on 18. December 2018, 0:46

The selection set "geo_set" should be inside the "peasant_A_RIG:peasant_A_RIG" selection set. You can remove the top selection set or unparent the "geo_set" if you want.

The writeVisibility flag is already set when exporting alembics from Maya. I just did a test with a box and a sphere. For the sphere I turned of the visibility checkbox in the attribute editor under display settings. I added both objects to the export state, exported them and in Houdini only the box was visible. When I turned off "Use Visibility" in the Houdini alembic node, then the sphere becomes visible. So it looks like the visibility was exported correctly. Maybe you changed a different visibility channel in Maya (like on the material) or something?

Quote from Magnus on 18. December 2018, 12:12

Aha! That makes total sense, thank you so much! I got it working now. The reason it didn't work before was that in my rigs I've used parent groups to store the visibilty, so on the geo itselt the visibility attribute was always set to 1. I spent the morning refocting the visibility swich setups in my rigs, and low and behold, now it work! Thanks a ton again for your input.

By the way, another thing I noticed is that material assignment is actually a lot easier than I thought as I only have to set it up once per character, as long as the geo is named the same in the export the material sop node can be reused 🙂

Quote from RichardF on 18. December 2018, 14:47

That's the beauty of Houdini ?

Quote from Magnus on 24. February 2019, 17:30

So my Maya to Houdini asset workflow is coming together really nicely, but I'm still stuck on the visibility issue. You see I need all the geo to be in the stream until the very last step, where I would like to blast the geo that should be hidden for that specific frame. Does anyone know if it is possible to store/bake the visibility data that comes with alembic to points or primitives?

Quote from RichardF on 24. February 2019, 23:18

I'm not exactly sure what your goal is. You have objects in an alembic file and the visibility was animated from on to off in Maya? As soon as the alembic objects get unpacked in Houdini the prims of invisible objects get deleted. But you prefer to delete the prims manually with a blast node instead?

You can set the "Load as" parameter on the alembic import node to "Alembic Delayed Load Primitives". Then you can access a lot of intrinsic attributes on the imported object. With a little bit of VEX you can use the "abcfullvisibility" and "abcusevisibility" attribute and copy them onto points and use them in a blast node or whatever you want to do with it.

Quote from Magnus on 24. February 2019, 23:27

Thanks Richard, I'll do some googling on those functions.

I know it's a bit of a wierd request, and not related to prism of course. It because I'm building an asset pipeline in houdini with zbrush and substance working seamlessly with already animated geo. That way I can give the animators rigs quite early in the process and skin some dummy geo, that very easily can be updated in houdini using a modified point deform. So I need all the geo visible thoughout the stream while going through the process, then at the very end I would blast the prims that should be hidden.

Quote from RichardF on 24. February 2019, 23:40

Ah ok. I'm working a lot with Houdini and I'm sure a few people here too, so feel free to ask if you get stuck somewhere even if it's not Prism related. If there's the need for that I can also open a new forum section for unrelated stuff.