Hi,

It seems that the mtlx subsurface shader in karma isn’t tagged with sss so it cannot be picked up by LPE so I was wondering how I can tag the BSDF nodes to be used in LPE.

The AOV and Dot node both seem to be unable to take a BSDF as an input and I don not want to do this on a surface level as I will be unable to layer other BSDF on top. Any ideas?

Best,
Rich

Hi. MaterialX BSDF labels in karma are hardcoded and you can't customize it, but its SSS BSDF does actually have the 'sss' label. There was a bug fix in 19.0.469 where BSDF labels weren't working in LPE. If you're using an older version I would suggest updating to the newer one and see if the issue persists.

Hi dlee,

Thanks for explaining this, I am currently on 0.455 so this explains why the SSS label isn’t working for me, I will give my Houdini an update

Do you know if there is any intention to make this not hard coded in the shader? Having an editable label on the MaterialX BSDF nodes would be incredibly useful in production to adjust specific specular lobes etc.

For example in a skin shader you could label a dielectric BSDF ‘sebum’ so you could adjust the sebum amount in comp without affecting the other specular lobes.

Just an idea!

Best,
Rich