a model that casts shadows on itself, say, you have the deathstar, with that tower thinguy where the emperor hangs around. If you put that in FS2, you'll get the basic shading, but you'll never see the actual shadow of the tower projected on the deathstar. with self shadowing, you'd have the shadow. But that's highly complicated. We don't even have projected shadows ( you can see the shadow of your ship projected on the ship next to it - if positioned so you should see it, of course ), which are probably easier to do ( shadowmap system, for exemple ), in Freespace, so that...