Cycles - groundplane and transparency

[Normand (Jakob Normand)]

Hi @nathanletwory
Inspired by Jørgen @Holo complaint on the OpenGL transparent materials, here’s something I’ve been meaning to report for a while. If the groundplane is visible through a transparent material, it looks as if the groundplane material is overridden by a default material. Is this something that can be changed/tuned up, or does it have to do with the weakness of the shadow catcher material - I seem to remember you indicating that it’s not really a “proper” Cycles solution? Attached is the same view with the groundplane as the default plaster material and the “shadow only” material. Notice how the groundplane - when seen through the glass - is the same on both screen grabs.

TIA, Jakob

[nathanletwory (Nathan 'jesterKing' Letwory)]

@Normand

Is this something that can be changed/tuned up, or does it have to do with the weakness of the shadow catcher material - I seem to remember you indicating that it’s not really a “proper” Cycles solution

It is a shortcoming in the shadow catcher feature of Cycles. This issue is still not solved upstream properly. For instance in reflections you’ll still get the ground plane as well.

In the future I’ll likely tackle, if not even rewrite the current shadow catching algorithm, but it is not top priority at the moment.