Hello @all,
i have a bunch of points and some gridlines…
i want to get the outline of the whole geometry and cut the lines with the region…
does someone has an idea of how to get there? 
thanks in advance
Upload a file.
oh yes - sure
internalised data.gh (9.7 KB)
okay, i got this one on my own
i patched the points to a surface, splitted it by the curves… and filtered the list to get the final result ^^
next time please categorize your topic accordingly that people not familiar with grasshopper dont waste their time making suggestions which are not applicable to you
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Just use the Boundary Surfaces component and then cast the output to a Curve.
Graph Space:
Model Space:
Patch and Split Surface are fine and all but they can get quite computationally intensive depending on the inputs.
Cheers!
3 Likes
@michaelvollrath oh okay 
thats a lot better - thanks!
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I don’t know if it has been exposed in vanilla Grasshopper yet, but the Curve.CreateBooleanRegions method seems perfectly suited for solving this problem:
240711_CreateBooleanRegions_00.gh (11.8 KB)
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FWIW, one can use Curve.CreateBooleanRegions for these cases too:
240711_CreateBooleanRegions_01.gh (5.4 KB)
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Thank you. I appreciate that the .CreateBooleanRegions works, but I still do not understand the difference between the examples I was testing and what the OP posted that makes Boundary Surface work on his curves and not mine.
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it`s a wild guess, but maybe it depends on how the curves are sorted?
It’s hard to say without a file to study/debug. But either way, when there’s a native RhinoCommon method that does exactly what the problem requires (I think), why not just use that method instead of hacky workarounds 
I do not think that this is the case since the order doesn’t matter if the curves do not extend past their intersection points in the corners, but I will try.
Mostly because I am not familiar enough with coding that I would have been able to use the RhinoCommon method without having an experienced individual like yourself simply providing me with the finished component. In other words, that this a problem for beginning and non-programming Grasshopper users.
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That’s fair. Maybe try posting the file and we can have a look.
I will have to recreate the file. Please give me a moment.
Here:
Boundary Surface Test on intersecting Curves with internal Region.gh (10.7 KB)
While the curves are internalized, I created them on the basis of Rhino geometry to make sure that the last set has knots that lie on the same corner points.
so i think it might have something to do with the “extented curves”…
give the boundary node just the segments of the closed curve of the object and it will work - but not for the pentagon in this example
Because the circle is not centered on the pentagon. But still, it is not a solution for a grid of lines that do not have a convex envelope (imagine a U-shape)