Clipper——offset polylines twice

[laurent_delrieu]

Hello
Many things are needed. You must provide all the polylines which are ONE border and THE holes. Then you have to take all clippers results and look if they are inside the shape. … some complementary tools must be done in order to do the job.
See these discussions

"spiralize" offset curves for fabrication

Hi, I want to modify these curves so I can use them as tool-paths. [image] The problem is though that due to the specifics of the fabrication process these can not be multiple curves – instead it has to be one continuous, smooth curve. The idea is to “sprialize” the curves like this: [image] For simple curves, with only one inner curve each it works like this: [image] >> [image] For curves with multiple inner curves I can’t quite figure it out. Has someone an idea to guide me in the…