Make one mesh invisible but still affect other physical materials

Hi! First, thanks for the awesome framework :slight_smile:
I am trying to build a Sphere that uses meshPhysicalMaterial. It is mostly transparent and the goal is to pick colors from a background that is changing with custom shaders.
I would like to make the mesh that is generating the colors invisible, but still have them reflected in the sphere. Any clues much appreciated!
I attach an image

i am feeding the material which isn’t rendered out otherwise to a texture which then uses it to refract. you can use the material from that box btw, the app is react but the material is a generic THREE.ShaderMaterial

ps, forgot to mention, it also injects a background hdr into the filmed texture, that’s what i’d do with the shader in your post, making that into an environment.

Man, this is a GEM
Thanks so much, I’m going to take my time to undestand everything that’s going on there :slight_smile:

A cube texture, made with PMREMGenerator from a big sphere with shader on the back side. Then applied to a small sphere as envMap.