Shader trouble

Houdini cannot resolver OmniPBR from exsit usd file
but it can be use from materiallib
And also, Omniverse creator 3.1 &3.0 cannot resolver Mtlx shader aswell…


the model itself are export from maya by defult setting
I am using simplest omnipbr shader to test it, also mtlx are stander shader

Flower1.usd layer contain shader and model infomation
test.usd layer only refrence background and make a tranform to model

so it isn’t a conplex layer stack

and btw, i am still confuse blender connector.
i have already test blender connector for 2day, but still can not understand how to export transparent shader as mdl, is that still not support?

Hi are you using an Omni mdl node after your import? What does your Solaris network look like?

Hello @Jiucao
do you have the Flower1.usd file that I can take a look here?

I am digging into the mtlx question as well now.


I didn’t create omni mdl node.
Solaris network just some refrence & merge node
Not something special…
not even create our cunston node

there is

Hello @Jiucao
sorry for the late reply. I setup a hip file to make the materials work in Houdini. Please see attached hip file.
mtlx.hip (145.4 KB)

There are several things going on -

  1. The material doesn’t work because the attribute info:mdl:sourceAsset:subIdentifier on the shader has an unexpected trailing string (color,texture_2d,float,......) Is it coming from Maya Connector export? I will check with our internal Maya Connector team and make sure this value is valid (or fix it if it is a bug.) In the mean time, the workaround is to put an Edit Properties LOP to modify the attribute. I have it in the hip file for your reference.
    We will also update Houdini Connector so it will handle this case better in the next release.
    A note to the "@OmniPBR.mdl@ -> Connot be resolverd" question - this is an expected behavior. The attribute is used by RTX renderer and Houdini does not know much about it. We only use it as a string instead of a resolvable Asset Path in Houdini Connector.
  2. I tested mtlx in Create 2022.3.1 by using the USD file exported from the hip file above. It renders for me - Please see attached image, the purple leaves are using mtlx.

    I also attached the USD file - you can open in Create 2022.3.1. For the first time opening that file, RTX might take few seconds to render the materials, but once it’s done, the render is fast. Please let me know if you can see the same result as the image above.
    Flowers1_mtlx.usd (89.2 MB)

Thank you for using Omniverse and the feedback. Your experience and suggestions are very important to us. It helps us building better tools.

Please let me know if you have more questions, I am happy to answer them. Faster this time ;)


Model are export from blender
Shading from maya
assamble from houdini

thx reply

That sounds good! good workflow you have there!
We have fixed the OmniPBR issue you had above in the next Houdini Connector release. Thank you again for reporting the issue!


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