Hey guys, just want to understand what caused it. Is it because of node redesign/refactoring or something else?

Going through Materialx repo I still didn't get it (found only Lama Add node): https://sourcegraph.com/search?q=context%3Aglobal+repo%3Agithub.com%2FAcademySoftwareFoundation%2FMaterialX+file%3Aadd&patternType=standard&sm=1&groupBy=repo [sourcegraph.com]

Goal: Combine 3 MTLX standard surface shaders to get a rainbow effect on CD. How it should be done properly?

MTLX Mix node "Mix" param is somewhat confusing when mixing so I need to eyeball it (I assume this is not how it is supposed to be).

Proportional mixing (40% from shader 1, 30% from shader 2, and 30% from shader 3) still didn't get desired result:
- first mix node value = 0.571
- second mix node value = 0.429 (1 - 0.571)




In H19.5, SurfaceShader signature is present, while in H20 it's gone (with a few other signatures):




Thank you!

That signature was removed from the MaterialX standard in 1.38.6 [github.com]:

- commit: https://github.com/AcademySoftwareFoundation/MaterialX/pull/1089 [github.com]
- meeting notes: https://academysoftwarefdn.slack.com/archives/C0230LWBE2X/p1664303114494509 [academysoftwarefdn.slack.com]
- original discussion: https://academysoftwarefdn.slack.com/archives/C0230LWBE2X/p1663675573355349 [academysoftwarefdn.slack.com]

First question is if there is a need for these at all? And that goes for all the shader types (surfaceshader, displacementshader and volumeshader). The one operator among them that I can see some use for is the mix of surfaceshader type, mainly to be able to have materials that mask out different surface shaders on different parts of an object.

In our opinion, these nodes should not exist. The only thing you should be able to do on shader types is blending them with a mix node, all other operations should be forbidden.

zdmit
Goal: Combine 3 MTLX standard surface shaders to get a rainbow effect on CD. How it should be done properly?

I would just add the bsdfs directly

Rafal, grateful for clarifications.

Jsmack, grateful for the thought!