Material Assignment Breaks When Trying to Render Materials Within Published HDA

[john_morch]

Rocky Linux

V-Ray for Houdini hash:82c1b12 from 19 Feb 2024 13:10
V-Ray Core 6.20.05 [31923cf8] from 17 Feb 2024

Houdini 19.5.605

V-Ray materials in a HDA do not work properly when assigned to material node.

Steps to reproduce:

1. Create a subnet in /mat
2. Add three V-Ray material builder nodes
3. Modify the V-Ray BRDFVRayMtl node in each material builder node and set the Color field to a unique color (ex. red, green, blue)
4. Name the V-Ray material builder nodes accordingly
5. From the subnet, create an HDA (default options are fine)
6. Create a geo node in /obj and create a testcrag node
7. Create a material node and set its input to testcrag
8. In the Group field of the material node use the dropdown to select a primitive name
9. In the Material field of the material node, browse to the created HDA and select a material builder node
10. Repeat steps 8-9 for the remaining two material builder nodes in the HDA
11. Create a camera and a V-Ray dome light
12. Create a V-Ray render node
13. Use the VFB to render crag

Expected:

The V-Ray materials in the hda are assigned to test crags selected groups. A unique color for each assigned geometry.

Result:

A single material is assigned to each group. If "/vrayOutput" is added to the Material path of the material node, things render as we would expect.

[bdancer]

Is it possible to share the hip file to make sure we are fixing the exact setup you have?

[Gosho.Genchev]

Hey john_morch ,

Could you please send over your scene with the HDA so we can investigate? I followed your setup and the result seems to match the expectations:



I've embedded the HDA in my file, attached below.

It would also help to give us the exact V-Ray build that you're using - you can find it under the Houdini Top Menu -> V-Ray -> About V-Ray -> Copy to Clipboard.

Best regards!

[john_morch]

bdancer Gosho.Genchev Thanks for taking a look.

V-Ray for Houdini hash:82c1b12 from 19 Feb 2024 13:10
V-Ray Core 6.20.05 [31923cf8] from 17 Feb 2024

Houdini 19.5.605

Rocky Linux

Attached is my setup.
I'll take a look at your file. Thank you!

[john_morch]

Gosho.Genchev I checked your scene and unfortunately, I'm still getting only one shader assigned to all the geo.

[Gosho.Genchev]

Hey john_morch ,

Unless you're locked to this particular V-Ray for Houdini build version, may I suggest grabbing a recent stable builds from the nightlies section? I double-checked to make sure this works as expected there.
You can find the stable builds here: https://nightlies.chaos.com/#/vray6houdini/stable/6.2

If you don't have access, the support team will be able to quickly provide you with it: https://support.chaos.com/hc/en-us/requests/new

Best regards!

[john_morch]

Gosho.Genchev I tried 6.20.23 and I'm still getting the same issue.

V-Ray for Houdini number:22761 hash:954828e from 22 Sep 2024 01:17
V-Ray Core 6.20.23 [e22648ee] from 12 Sep 2024

I've attached my test file for 6.20.23.
Are there any V-Ray environment variables, V-Ray render settings or VFB settings that could cause this to happen?

[Gosho.Genchev]

Hey john_morch ,

Here's 20.5 with the stable build you're using, and your scene:



Here's 19.5 with the same setup:



I see in your scene that the Renderer ROP is set to "Export" so I assume you're generating VRScenes and sending them to a render farm - what is the V-Ray version deployed on the render farm? Ideally, it should be the same stable build that you're working with on your workstation.



Best regards!

[john_morch]

We do export out scenes on the farm and then have a separate vray standalone render job. But the tests I was running were all local. I changed the "Export Mode" to "No Export" and that didn't make a difference either- again running locally. Must be some other setting or environment somewhere causing this issue on our end. Either way, we've updated our tooling to just add "/vrayOutput" to the material path. Thanks for the help!