Backplate

[ronjart]

I was wondering if anyone had a good workflow for creating a backplate. Doing it in post can be tricky since the opacity map on leafs (for example) doesn't render out in Material ID pass. Doing an emissive diffuse material on a plane can be a little cumbersome.

I'm thinking of Vray and the two dome light approach (one for lighting and one for background image). I've tried to make a simple sphere and play with the object properties like "don't cast shadow" etc. with no results.

Any ideas?