Shadow catcher with opacity map

Tue Jan 14, 2020 7:39 pm

hi All,

In our studio we doing a lot of quick octane renders when designing the products. Constant flow of design iterations. We using Rhino+Octane. Render setup is simple - product with shadow catcher on white background.
Up until recently for Shadow Catcher we used Diffuse material with Shadow Catcher ON + Texture map (black/white, round circle) for Opacity Channel. This give us ability to control how far shadows spread out. By controlling it this way we can make sure that we always have "clean edges" of the renders. By "clean edges" I mean pure white.

Without Texture in Opacity channel, shadows can spread out all the way to the edges of the renders. This creates a problem for us when we compose multiple renders on the single page of the document. You can see edges of the renders (yes, this can be fixed in PS, but it will take a lot of time to do this for multiple renders)

Workflow with Diffuse material + Shadow Catcher ON + Opacity map worked in Octane 4.5.0.111 for Rhino.

Now we updated to Octane 2019.1.4.115 for Rhino. And this workflow doesn't work. There's still Shadow Catcher option available for Diffuse material , BUT as soon as texture map plugged in into Opacity Channel - shadow catcher doesn't work.
I see that now there's a specific material type - Shadow Catcher, but there''s no Opacity channel available for it.

I asked this in Octane plugin for Rhino forum, and Paul (face_off) refereed me to General Questions forum.

So, question - how to create shadow catcher material with Opacity map ???

Thanks.