inner Shadow

[FSGFX]

is there a way to get something like the 2D inner Shadow in Photoshop.?
but i need it a bit more advanced... it should also work with self overlapping geo...

i cant use a directional light cause i would get a soft falloff on a sphere for example... i need to clamp the fake shadow to a max thickness...

any ideas..?

[FSGFX]

looks like i have to do it by hand...