Offset polyline

Can anyone tell me why I can’t offset this polyline curve down 12". When I try and run the offset command from the front view I get lines above and below and some missing.

Hint: you can upload files here directly… Just drag and drop the file into the message window. People don’t necessarily want to deal with going through Dropbox to get a file.


Like this? Thanks for the tip.
Offset Crv.3dm (73.6 KB)


As Offset is kind of a planar operation, Rhino doesn’t like to offset 3D curves that much… One workaround is to split the curve at the 90° corners and offset the individual parts using Front and Right views, then re-join.