I'm currently trying to figure out how the shadowing system is setup inside the current source code (well, 4.0.1 to be exact).

Currently, when you disable the "Cast Shadow" setting on an actor/primitive, it also disable the self-shadows. I'm looking for a way to only display the self-shadow.
I'm currently digging into the source code but it's hard to figure out something. I looked inside Source\Runtime\Renderer\Private\ShadowSetup.cpp for example but it's not easy to understand everything going on here.

Any hint would be appreciated.