Curve along irregular geometry


I’m developing a project and i can’t create in grasshopper a internal spiral or with straight sections circulations. Can someone explain me how to do it please (i uploaded de grasshopper file and a image of what i need). Thank in advance.


Please :pray: :pray:

You might try adapting this? (12.6 KB) (17.2 KB)

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I’ll give it a try. thanks for your response. :wink:

I think it will work but when i try to extract the endpoints of the curve they’re not aligned. How can i fix this?. Thank you.


OK, I had forgotten that the other model expects a round cone centered at World XY so it may be no help at all in your quest. It took me a few seconds to copy the old model into your model, then a few minutes to locate your “base plane” and a few more minutes to refactor your code so that multiple references all use the same plane, removing redundant code that defines it.

Unfortunately, it doesn’t turn out well and I have no more time for this now, sorry. Good luck.


Thank you very much for your time! :grinning: :grinning:

How about this? Note that your model was actually two breps, not one; I didn’t notice that before. So I joined them with SUnion and then sorted its edges “along” a circle, because the vertical edges on the bottom portion were in the opposite order from those on the top portion.

CullPt was necessary to remove duplicate intersection points at the seam between top and bottom. Why Series? It’s simple in concept but complicated to explain… :wink:


P.S. I probably should have filtered out all the horizontal edges and used only the verticals but I didn’t see any problem in this case(?), so didn’t bother.

That’s perfect, was having some trouble with the curves and the straight lines looks better!. Again, thank you so much!.

Getting a curve instead of a polyline from those points is easy, eh? Why not have both?


P.S. I see a flaw now that I didn’t notice in version ‘b’. A cross-over of the spiral(s) at the seam between top and bottom. I know how to fix it… Will get to it eventually, unless you beat me to it?

I knew I should have filtered only the vertical lines in version ‘b’ but was too lazy, White group.


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This is a pretty cool idea. Not that random is better by any means than individually located points, but here’s a riff on a different method for creating the base shape.


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