Void sweep in Dynamo

Revit
1

Hello!
We are a Group of students, who are trying to parameterize a Concrete slab in Dynamo. We need to make a void sweep extursion around/underneath the slab as shown in the Picture.

Detail_floor_sweep
Detail_floor_sweep848×548 1.21 KB

I have tried to use the node “Surface.BySweep”, to make the geometry of the extursion. Are there any nodes which could make these Surfaces into a solid, and then into a void extursion?

Surface.BySweep
Surface.BySweep1518×807 105 KB

Thanks for any help!

Dynamo script:
void sweep.dyn (49.6 KB)

2

Maybe this will be useful? Dynamo Dictionary

Also a Polycurve.ByJoinedCurves node may be a better use than the curve.join node.