Currently, I am rendering some extra masks out for an animation, basically the attached image.
if I render normally, with 10 passes it takes 19 seconds a frame, 10 of which is rendering.
If i render with a region drawn, either a max or corona VFB region it makes no difference, the time drops to 7 - 8 seconds a frame. and render time is around 1 second for the exact same mask.
Drawing regions won't really work in scenes where you need lots of additional masks or have more extreme movement
Can we have a more intelligent system that only renders/calculates what it needs to instead of calculating the entire scene? This shot is 150 frames so without drawing a region I would be waiting over 45 mins instead of about 18