Is it possible to render Cryptomatte pass based on a string primvars on OpenUSD point instance?

[han_ho]

Hey,
I am trying to render Cryptomatte based on point instance string primvars in usd file.
The usd file is created in Houdini and render with VRay Houdini just fine. However, VRay Maya render just red color, which probably means it failed to read the primvars.

To be able to render crytomatte based on point instance primvars is a very useful feature. Creating custom masks for million instances without this feature will be a nightmare. Is it possible to do this with VRay Maya?

Houdini setting, ATTR1 is the attribute name


Maya Cryptomatte render element setting



VRay Cryptomatte rendering from Maya(left) and Houdini(right)



The attachment is the usd file created in Houdini
string_primvars_on_point_instancer_for_cryptomatte.zip


Testing Environment
Windows 11

Maya 2023
VRay for Maya 6.20.01 and 6.20.24

Houdini 20.0.590
VRay for Houdini 6.20.05

[tsvetomira.girginova]

Dear han_ho, hello.

Thank you for the interesting topic.
To elaborate more - is Cryptomatte working in V-Ray for Houdini with the shown setup?
I am asking because the screenshot from VFB is only from V-Ray for Maya, and it is not visible which Crypto type (Render Output) is chosen to be shown in viewport.

Please share with us also the .hip file to investigate in details.
Best practice of sharing V-Ray for Houdini version is by pasting the information from V-Ray > About V-Ray (there is a Copy to Clipboard button).

Waiting for the information.

Best regards,
TS

[han_ho]

Hey, it does works in Houdini. First image in my previous post is what shown in Houdini VRay viewport. I rendered it to exr, and it works fine in Nuke.
Here is couple examples I put up with in a hip file. All works in VRay Houdini, but not VRay Maya.

cryptomatte_test.zip
Note that USD assets in TestB was exported directly from Maya, so you wont see texture because of absolute path.

V-Ray for Houdini hash:82c1b12 from 19 Feb 2024 11:02
V-Ray Core 6.20.05 [31923cf8] from 17 Feb 2024

V-Ray 6 for Maya, update 2
(v6.20.01 from Mar 25 2024)


Best,

Han

[tsvetomira.girginova]

Thank you for the provided files and details!

I will check everything out and write back.

[tsvetomira.girginova]

Hi again,

After performing additional tests, the information was just logged in our system for further dev investigation with VMAYA-13301 number.
You will be notified by any change.

Thank you once more and let's welcome 2025 with less issues and more joy ")

Best,
TS