View Full Version : Refraction and Alpha Channel Dilemna

03-28-2018, 05:27 PM
I have a solid object, unseen by camera, behind a semi-transparent and refractive object. I want the unseen object to be REFLECTED in the semi-transparent object, but I do not want it to be REFRACTED by that object, only the ones I want nearby. I know, it's a weird ask. I'm pretty sure there is no way to disable refraction rays separate from reflection rays, but that's exactly what I need.

Here's the scenario... a leaf and a rain drop, both reflecting an unseen textured sphere (cloudy sky). The rain drop needs to refract the leaf AND have it's gradient transparency preserved in the render's alpha channel, BUT because it refracts the solid, unseen-by-camera sphere, the rain drop alpha becomes solid (white) as well, as physics naturally dictates. I just need to break that law of physics. hehe

DOH! And I just did! How?

You have to SET THE UNSEEN-BY-CAMERA OBJECT'S ALPHA CHANNEL (SURFACE ADVANCED TAB) TO CONSTANT VALUE OF 0! YAY! Basically, that makes it "unseen by alpha" and thus refracted rays of that solid object in a very hacky sort of way.