I have a setup where I have one collection that is a background and one that is silhouetted against it. Each of these is in it's own View Layer. The background one rendered straight, the foreground one is lit brightly, rendered and then inverted.
My World is a starfield generated from a noise texture. The problem is that if I have world enabled, the inverted foreground layer creates an inverse starfield, completely blanking out the background layer.
I have found a few questions around this topic ( for example 'One render layer with background image and one with transparent background' ) but they are old and they talk about enabling
environment rendering which doesn't seem to exist any more.
So, in Blender 2.8 how do I render my world once rather than once-per view-layer?