looks like a bug of offsetCrvOnSrf to me.
splitting with shrink
… nothing helped
and a simple example from scratch show s same behavor:
offsetCrvOnSrf_bug.3dm (63.1 KB)
ok, the bug returns a self-intersecting curve
you can find this self-intersection by
for me the point did not work for trimming both ends …
fast and dirty:
draw a sphere arround that point, Radius 0.1 or even 0.01
use this for trimming.
now you can close the curve with
_makePeriodic (you will get some deviation)
or “bridge” the gab with
maybe more precise:
use _cplane _curve to set a custom cplane perpendicular to the curve at the self-intersection-point.
use the plane to trim
_match the curve ends against each other