Reflection catcher in cycles?

[harleynut97]

I’ve been composting 3d animations over backplates, making use of planes to catch shadows. I’m using cycles.

But I now have someone falling into a pool, which because water is reflective, I’d like to composite a proper reflection of the character who is falling into the pool to reflect on the water surface.

The water is already rendered on the backplate, so I need a node set up to work similar to how people composite shadows with cycles, but only for just reflections.

Is this possible?

[28selves]

You need to create water surface geometry or use existing one (if it’s model too as i believe) make it visible just to camera rays, place only glossy shader with zero glossiness, makr your character mask layer so you will achive just reflections on black background then compose it (add mode) on top of your back (you can compose glossy passes (dir+indir)*col).