Right now I'm trying to get a shadow catcher like effect on an animated scene. Please pardon the horrible test scene. I'm not new to 3D but very new to real time work and just learning.
The way I'm hacking at this is to use an emitting surface that is the same color as my background as a floor plane, but with no color, and then cranking up some of the screen based ambient occlusion (SSAO).
That's obviously far from perfect as it means that I have SSAO kind of going over kill on my other items AND if I apply bloom (esp on white background/floor) I get bloom everywhere. Dreamy but not what I want.
What's the best way to fake it? Use some geo with some maps on it? That wouldn't change though with my geo as it moved. Is there some old school game way to flatten out a copy of the mesh on the Y axis, and use that as a shadow or something?