Spline interior filling?

Is it possible to have a closed flat (2d) spline fill its interior in with geometry? (without making it in an exterior modeling package). If anyone could comment on the basic implementation/structure of such a feature I would be very grateful.

First post ever, sorry if this thread is in the wrong section and what not, but I’ve been looking for an answer for this one for a while now to no avail.

I’m getting the same, anyone?