Extracting interior polygons from set of intersecting open or closed curves

Hi All. I made this sort of manual interface for extracting the closed polygons/polycurves from a set of curves.
Made a bounding surface, split it with the curves and selected/extracted the interior polygons (if not enveloped by original curves it should not be selected).
Is there a cleaner way to generate this interior closed polygons and output them to a cleaner set?
A premise is I can´t custom code… (but readily available plugins are ok)
BTW I did search before asking :slight_smile:

Thanks in advance!

Is this what you want?

interior polygons.gh (10.5 KB)

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Kind of. I´d like to avoid the need of a surface.

Do all the curves live on one surface? Maybe you should post a file yourself first.

Polycurves/lines are intersecting (all flat, sorry for taking it as obvious).
My approach is the one above and is NOT what I need.

interior polygons-b.gh (10.2 KB)


It works but I have to resort to building the surface and splitting it again and extracting the contours.
Should be a way of producing this result faster/cheaper, right?

several possible approaches in additon to Ethan’s:

-The ‘polyline offset’ from clipper has interior and exterior outputs, you can offset each curve by a small amount, 0.0001

  • use ‘geometric region’ from heteroptera

Geometric region from heterotptera was just what I needed! Thanks!!