OK, I’ve been working on this as time permits for a couple of weeks, and been making some good progress.
Since the question of a Cycles shadow catcher comes up often, I’m writing a plugin which is pretty much a one click solution.
I did my own testing and found what I considered to be the best compositing node setup, and then I extended it to allow direct compositing over a background image (the original didn’t), and I’ve also added very slightly to the tweak options to circumvent an issue when you over compensate the levels on the comp.
It will handle shadows, reflections and reflected light. The option to directly composite the background is a separate toggle for those who prefer to do that in post.
It uses 2 scenes, 4 render layers, all set up individually, and three object layers. It isn’t ready for release yet, but I expect to have a release candidate in the next couple of weeks.
And, it will be free (as in beer and in license).
Development has been slower than I would like, since this is my first blender coding (I’m familiar with python, but not the blender specific side, so I’m having to research as I go). Nevertheless, I hope that there will be interest and it will be of use until a Blender native solution comes along.
Up to now, I have the node setup working, and the scenes are properly created but need a little tweaking. Once they are done, and the render layers setup correctly, it’s good to go to all you lovely beta testers out there.