everyone. I'm have been working on this project and need the hdr background to be on its own layer. I have a bunch of layers that I have put the main objects on and they all have alphas on them so when I go into compositing I just use an alpha over to combine into a single image. The only problem is now my hdr background has turned into complete alpha as it doesn't show up on any of the layers. I would like to have it on its own separate layer so I can add some effects to it in compositing. How would I go about this? Thanks for the help!
The way I did this was to do a dummy run render of the camera's motion within the environment on an empty scene layer, with the environment set to be "visible" to camera, and saved this as a file of PNG's. Then set up your scene proper, set the film to "transparent", check "use environment" on your render layers, and set the environment itself not to be visible to the camera. Finally, in the compositor, bring the environment back in as an image (set to image sequence), and alpha over the rest of your scene.