Major Project: Scene Cleanup #5 - Background Passes

Since I began rendering some of my heavier scenes before I realized my textures worked better with auto-bump rather than normal maps, I wanted to see if there was a way that I could render out just the background rather than have to render out the whole scene again. After some research, I found that by enabling matte, setting the matte colour to black and the opacity do zero under  'Matte' tab on the aiStandardSurface shader (for the gem/needle texture)... I could essentially cut out just the background for re-rendering.

I can then bring the two renders into After Effects and place the new background on top of the original render, so the new background covers the old one. I did several tests on both the gem and needles using saved stills as well as a few 'Render Sequence' frames to ensure this worked properly. It seems to work as I was hoping it would, which is a relief since just the background doesn't take as long to render on its own. Having these passes is actually useful because now I can adjust the colour correction/brightness of the gem and room separately. This technique may also be helpful for future renders, such as skin since the room itself doesn't require subsurface scattering but the orb will.