Question: Outline/contour of both open & closed curves (Grasshopper)


I am on Rhino7 and this concerns Grasshopper. I like to generate the outline/contour of a combination of closed & open curves. I have tried “boundary surface” and other components, but they all fails for different reasons.

What would be the simplest way to connect these curves and generate a list of single outlines/contours in a list?

Thank you for taking the time!


Closed & Open (8.2 KB)

You can create Region intersections like this:

Closed & Open (11.7 KB)

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Hello Martin,

Thank you, that works very well! “Region Union” is the key. :slight_smile:

Now I’ll have to work out what to do if the primary (closed) curve has a concave curvature, however, that should not be much of an issue.


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Extend the ends of the short curves and then use Region Difference

Closed & Open (14.8 KB)

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Thank you, Martin, that is a great idea. Will do!

Have a nice day!

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