It’s very interesting, it helps preventing light leaks when you use dynamic lights or shadows that don’t start close enough to the source object. It was very annoying in the past. Particularly nice for exterior scenes when you don’t always need/want to bake anything. It’s enabled by default, just need to increase the length.
Here’s a quick example.
Contact shadows length 0
Contact shadows length .05
wowww!
it is only for dynamic lights?
Well, it wouldn’t be useful on a baked scene, since you’d get better contact shadows anyway. It’s good for objects that are lit by movable lights. It seems like it’s a screenspace effect.
oh ok! if it would be useful for baked scene, it is definately a milestone for archviz. you know we’re doing lots of things (increasing lightmaps, decreasing static lighting level scale…) for eleminating light leaks and it costs very expensive.
It does work on baked lighting from what I noticed. It may help cover up light leaks and increase shadow detail when using lower resolution light maps. But I’d have to do more testing to see if it’s actually completely arch viz viable and works in most situations though, and if you could actually get away with a 128 bake looking similar to a 1024 bake, for example. Probably should keep the value low, like around .1.
I don’t think so, since it’s a screenspace effect, it can be kinda noisy. I had to increase my screenpercentage to 200 make it look good.
I wanted to add, it works with stationary lights, but not static lights. If anyone wanted to experiment further with it.