The white surfaces are duplicate. They are full surfaces (edges are natural).
The red surface was made by _Fin of the edge of the white surface.
The green surface was made by _Fin of a _DupEdge of the edge of the white surface.
I expect the red surface to be the same as the green, without the extra knots.
Fin_Edge_vs_crv.3dm (44.7 KB)
This occurs in 7.16.22067.13001, 2022-03-08 as well as in V5, V6, and 8.0.22067.16305, 2022-03-08.
Hi Steve - I would expect that as well, I’ll add this to the pile, thanks.
RH-67883 Fin: More complex with duped edge
_OffsetNormal also produces different output depending on whether the input is a curve or an edge.
looks like this got changed for V8, but does not take care on precision - see this topic:
produces imprecise results on untrimmed surface edges. - especially regarding its height / distance from surface.
the workaround is to use _offsetSrf (solid = yes) and _explode and only keep the needed surface
example shows a “20mm” fin in a document with 0.001 tolerance.
the marked position is 20.014mm
fin_imprecise_bug.3dm (64.1 KB)
Maybe a solution:
and explicit tolerance (which should be document tolerance by default)
kind regards -tom