Hi Jason,

re:
> Is there a better way? The docs seemed to say I could take the inner perimeter
> (which is non-planar), and then draw another straight line and boolean form them
> into a floor. But I couldn't make that work...
> I guess it only works for planar, and not organic?

It's not that it's organic vs planar, it's that your object is an open surface instead of a closed solid.

Booleans are focused on working on solids, they determine which pieces to keep and which to discard based on what solid volume they are contained inside of.

When your object is not a closed solid you will usually need to use Edit > Trim to cut it rather than booleans.

The Edit > Trim command cuts curves or surfaces and then you manually pick which areas you want to keep or discard, then you use Edit > Join to glue the trimmed surfaces together.

Booleans are kind of like a "batch mode" that does that whole job of intersecting, discarding and joining all together in one operation so it can save time but your object needs to be a closed solid in order for the booleans to be used.

- Michael