You would need to select the intersection points and control points at the perimeter (assuming they are at the edges of the surfaces), then create a floor object from the footprint of the combined surfaces. I believe Clockwork package has a node which takes a floor and points and pulls the floor to those points, however the big limitation is the fact it will be faceted. That’s floor objects for you.
The only exception to this rule, where floors can exhibit double curvature, is when a floor object comprises four points and one of the points is moved out-of-plane.
I have uploaded a revit project with family in - the aim is to make the adaptive component either floor/roof/ceiling? to make it room bounding for volume calculations.
That works, but Revit is being awkward as usual and it isnt seeing it as a bounding element ( i guess because of the small holes within the adaptive family) and that its more of an organic shape?