Offset 2d curve in cplane


Greetings - how can I have Offset Curve ignore self-crossovers in a path?

Simple examples: classic 2D picnic table or bowtie polyline curves in cplane.

Trying to create a ribbon from the closed path defining a Celtic or Tibetan knot using offsets. Knot path has several 90 deg.crossovers - I will edit the ribbon to depict the over-under weave.

Seems Offset Curve hits the first crossover and turns back towards start instead of proceeding through all the crossovers to end of closed path.

Edit points in path at crossovers have been deleted.


Tom Longtin

(Pascal Golay) #2

Hi Tom- from a simple bowtie polyline and one offset operation, what is the expected result for you, if it worked as you would like?



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Thanks, Pascal =E2=80=93 I found a simple enough workaround to offset at =
self-crossovers and the problem may not be serious enough to address.
I was surprised, however, when it happened even tho I removed points at =
the crossover intersections.

The closed green polylines below are the target for offsetting on both =

Splitting the closed curves into 2 open curves without self-crossing =
works OK.
Just need to do some trims and curve extensions to fix.

Best regards,