I have a problem that I want to solve if possible.
I have 2 objects (Boxes), Obj2 is above Obj1 (almost touching each other on Obj1's Z+ face). I want to draw Obj2 only in where Obj1 is visible to camera ray. So if I can see Obj1 through X-Ray the Obj2 is drawn. I know that OpenGL has stencils, this is what I want, but I didn't find it in Blender.
Mask Passed is what I will have in the render (after shading).
Mask Failed is what will not be drawn (This is what failed the comparison inside the stencil, like a inverse mask)
I think Booleans won't work here because it has nothing to intersect with.
So my question is: Is this possible without hardcoding them both in Eevee and Cycles? If I change the Loc/Rot/Scale of the camera the stencil must be calculated automatically.