Hey guys,

I have a shader which has no opacity shader attached but when writing out the USD it seems to connect my diffuse to the opacity.

Its doing nothing when reading back into Solaris but when reading into Unreal engine, its causing all my asset materials to be set to Translucent instead of Opaque.

Any ideas on the cause?

Thanks all,

Dan

I have the same problem, and apparently it's seems to be a "feature" cause it's written in the material libray doc -> https://www.sidefx.com/docs/houdini/nodes/lop/materiallibrary.html [www.sidefx.com]
Unfortunately it's breaking a lot of things, even their magic market demo files broke when you rewrite the usd files in a newer version of Houdini...

Daraminix
I have the same problem, and apparently it's seems to be a "feature" cause it's written in the material libray doc -> https://www.sidefx.com/docs/houdini/nodes/lop/materiallibrary.html [www.sidefx.com]
Unfortunately it's breaking a lot of things, even their magic market demo files broke when you rewrite the usd files in a newer version of Houdini...

Ah yes, it says so here:

Note, if textures are involved, the auto-generated preview network will wire the alpha output of a USD Texture Reader primitive to the opacity input of a USD Preview Surface shader primitive. Some renderers, like Storm, are known to mishandle the opacity, leading to artifacts in the viewport. To workaround such cases, you can turn this toggle off and then you can manually create a USD Preview network inside, feeding it to the Collect VOP along with the original surface shader.

It would be great if this could be optional and defaulted to off but there must be a good reason why its defaulted to on. Hopefully sidefx can clarify.

Thanks Daraminix

There's a checkbox for using the basecolor alpha on the principled shader. It would be nice if the material library respected this toggle when translating the preview shader.

While H18.5 does not respect "Use Texture Alpha", the development branch (H18.6) already does respect it. It's just not backported, because some changes that made it not trivially backportable.