Kinked and folded curves - split

I need to split planar curves which fold back on themselves at the fold using Rhino commands. An alternative would be snap to the fold. Two simple examples in the attached file. FoldedDC01.3dm (32.7 KB)

Hi David - the best I’ve been able to do so far is use Split > Point and drag as far as I can go off the ‘end’ without getting the no-no cursor and click…

-Pascal

Thanks Pascal. That is also the best I can do, but I’m hoping for something with guaranteed results. Dragging to the end usually works but you have to be careful.

Hello,

hope this helps. You can open it up in PythonScript

SplitFold.py (1.2 KB)

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I only spend 15 min on this so I know that this is far from a reliable command, but at least you could have had a look on it, so that it serves as a proposal for further work. The basic idea is to look for cp arrangements which are close to antiparallel, and getting the cv where it flips and its closest parameter. Greville point should have worked here in first place, but for some weird reason it was not the closest point to that cp, so I had to use “curve closest point”

nice idea! That should work.

-Pascal

Thanks for the script. I need to study this to understand it.

“cv” is shorthand for ???

‘Control Vertex’ (= control point, = cp as well, in that post, as far as I can see)

-Pascal

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@TomTom 's method is very clever. (Meant as a compliment.) The curves in my file were created by projecting curves onto a plane, and the kink generally does not lie at an edit/Greville point.

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@davidcockey @TomTom
just my miserable note
I know the comment 4 years ago but maybe it will be beneficial - not to forget to normalize both vectors before sending them to the dot product, it allows scale and unit independent calculation and helps in the case of significant vector length difference or vice versa a very small difference (when you set threshold)