A little embarrassed– the shot seemed easy enough, but it's really throwing me for a loop. There is a bloodstain on an elevator door that needs to be removed. However the shot is a dolly push in and the character crosses the stain, casting a complex shadow across it.
Can anyone better experienced chime in on some technique? It's mainly the shadow that makes it so tricky.
It wasn't quite as bad as I thought – I was even able to avoid tracking. I roto'd the character whenever he crossed the stain, masked out the stain throughout. I duplicated that base layer and slid it behind the mask, aligning the top the door. I applied a simple level to match color, and then for a shadow, put a BW gradient on a solid over the fill layer, rotated it to match the angle of the shadows in the scene, and the keyed the position to match the shadow going across. I messed with opacity of the shadow to further integrate.
Whew! Hope this helps some noob like me sometimes.