Keerah
Not fixed!
Same behavior on build 21.0.566 mixing surfaces

Do you have some materials in your scene that was carried over from an older version than Houdini 21?

Heileif

Keerah
Not fixed!
Same behavior on build 21.0.566 mixing surfaces

Do you have some materials in your scene that was carried over from an older version than Houdini 21?

Actually yes, I do
I updated all the normal maps to 2.0 though, haven't seen anything else to update.

When using material libriay, it seems can be temporary fixed by copy and paste the malfunction mat node while delete the origin one, though warning will pop out after reassign mat to geo

Hello!

I get the same error, but due to use kma_tangentrotate on an openPBR shader.
If I unplug the node, the error goes away. My viewport is also broken, but render seems fine.

Thanks for investigating.
Best
Stefan

Same bug with the 21.0.596

We got rid of the problem by deleting a mix node connected to an Material Outputs node.
The mix node was connected to a mtlxstandard surface and an unlit node as inputs.

Hope it can help

Tylius
The mix node was connected to a mtlxstandard surface and an unlit node as inputs.

This is a different thing, a limitation actually, currently you can't mix different surfaces using Mix. Houdini gives you a warning when you try.