Houdini Engine / Maya Instancing / Vrscene

[Akarsh]

Hi. I'm loading a HDA into Houdini Engine for Maya that creates various instances using Maya's particle instancer. I'd like to bake these to vrscene files to be rendered in Vray standalone. Is this possible? The currently created vrscene files don't contain any of the instanced geometry. This is using Maya 2017 with Vray 3.52.

If not, are there any workarounds?

[Gosho.Genchev]

I remember doing something similar 2 or so years ago - I had an asset that simply scatters points on an input geometry and creates the orientation attributes for the Maya instancer. The output of the Hou engine asset was simply a particle system. So it's possible - I was using V-Ray to render my scenes back then.

The instanced geometry should be exported to the vrscene straight away - there must be something fishy going on. How exactly are the instances generated ? Are you trying to Copy / Instance the geometry inside the Houdini digital asset ?

[Akarsh]

Hi Gosho. Internally the asset loads a sim from disk and replaces the geometry with high res versions also held on disk. It's pretty much a file sop and a few wrangles, nothing fancy, but the output is already instanced geometry (At least in so far as it uses Mayas particle instancing system - Is this practically any different from having the asset output a point cloud and then doing the instancing as a separate step afterwards?).

[Gosho.Genchev]

Hello,
that could be the reason but then again, it would be pretty hard to replace the pieces in Maya rather than doing it with Houdini's functionality. As far as I know, the Houdini Engine has never been extensively tested with V-Ray for Maya, and official support is not implied.

Is the geometry rendered correctly with Maya's Software renderer? If so, it should be supported by V-Ray as well.

If possible, send a ticket to support at chaosgroup dot com with the hip file and the asset so we can take a look.

Cheers !

[Akarsh]

Ok Gosho thanks. I'll prep a package and forward it onto support. I'll post back if there's a resolution in case anyone else is looking later.

[Akarsh]

Ok so the resolution is this should work fine - Must have been an issue with the scene I had initially, or a problem on the Deadline submission side. I do seem to get less issues in general (more stability too) since having updated Maya from 2017 to 2018, but there should be no issues writing instanced geometry into vrscene files. On the contrary if you output to a single file rather than a sequence it's incredibly efficient, as it only needs to write the geometry once and then update all the transforms per frame.