ruled surface (loft) using ThruSections

hi,
i need to construct ruled surfaces from two (not closed) wires.

However, depending on the order in which the wires are supplied to ThruSections, the result is either as expected or "twisted" (looks like an hour glass).

How can this be controlled? And why does it matter anyway?

Thanks for any help
Holger

h-ettinger's picture

A follow up to the previous message:

I had a look and found various (corrected) bugs regarding ThruSections, e.g.

788 ThruSection cannot determine the correspondence between wires correctly
789 ThruSection algorithm produces an oscillating surface.
895 BRepOffsetAPI_ThruSections creates a twisted surface.

Does anybody (from OpenCascade?) know, when those bugs were corrected? I still use v4.0 (I know, a bit outdated) and it would be very interesting to know whether those bugs were still present in v4.0.

I appreciate any suggestions
Holger