Extruding non planar curve

Why extruding non-planar curve does not result in a solid when solid option is “yes” within Extrude command? How to make solid?

Hello - that has always been the case - there is not a way for Rhino to reliably build a cap surface on an arbitrary non-planar curve.

-Pascal

Pascal, Can you point me to info on how to construct a non-planar solid?
Thanks

Hello - my guess is, with this example, you can Patch the top and bottom edges and Join.

-Pascal