I´ve created a volume from a set of wires defining a loft, a frontface and an opposite backface. The building steps were:
1.) generate 5 "Guiding-" Wires (each of them are non-closed)
2.) Build an open Shell from these Wires with BRepOffsetApi_ThruSections()
3.) Attach the Frontface and the opposite Backface with BRepApi_Sewing() to the open shell of step 2) to form a closed shell
4.) Build a volume from the shell with BRepBuilderApi_MakeSolid()
You can see the volume in the attached bitmap.
My problem is, that the use of BRepGProp on that volume leads a negative value.
I think, this has to do with some faces having a wrong orientation. I tried to flip the frontface and/or the backface (by changing the order of the underlying Points) but the volume still computed negative.
I would be very appreciated for any hints about this problem.