I need to take a small snippet out of a circle with a specific length. Pretty easy to do with the Arc command in Rhino but I’ve been racking my brain how to do it in grasshopper. Any hot tips?
the Evaluate Length component can be used to find the point at (and the parameter along) the curve at a certain length from the starting point. Do note that the default behaviour is for the length to be ‘normalised’, that is 0.0 = start, 0.5 = middle and 1.0 = end of curve. To use absolute length you have to set the N input to false.
The attached file will work on any kind of curve, not just circles.
arclength.gh (10.6 KB)
Oh well, David beat me to the punch but here’s my solution, assuming that you wanted to extract a snippet of specified length starting at a point in the circle and the snippet is smaller than half the length of the circle.
Snippet from Circle.gh (9.7 KB)
Awesome, thank you both! Any way I can control the rotation or quadrant it’s snipped from?? Trying to end up with a straight section. Like a crescent moon.
like this?
arc.gh (9.8 KB)
If I want to keep only the snipped portion and remove the rest of the circle, could you kindly assist me with how to do that? I would really appreciate your help!
In Ethan’s example, since it’s already being sorted by the length you can simply change the List Item selection. The last item of the list (-1) will be the longest, and by default, 0 will be the shortest.
In the other examples above, the initial curve direction is determining the selection, and a Flip Curve would suffice.
Snippet from Circle2.gh (11.5 KB)