Curves cutting an spherical surface and join their centers on surface

I'm trying to do this.

A nonplanar surface trimmed by closed curves on it and then join their area centers by the shortest curve (on surface)

Picking up a sphere, for example.

The problems:

i dont know how to those circles, be part of the surface instead of just planar. I tried projecting but it generate the circle on the other side of the surface.

An about joining the centers, i Only found curve on surface that generates a nurbs curve not straight lines on the surface.

I'm just starting with grasshopper.

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curves.gh, 8 KB

Replies to This Discussion

Permalink Reply by ng5 Alex on April 8, 2015 at 3:21pm

Hello Sergio,

you can try the following

you evaluate the surface at the given UVs from srf closest point, getting access to normals at these points. These normals are used for the circles projection on the sphere. Now you get two projection for each circle. You can use larger than to cull the distant ones and have the closer projected circle according to his initial planar one. using surface split component you get the partial surfaces of the sphere. using again larger than testing against areas, you can get rid of the rest of the sphere. closest points component (N=2), will output the closest two points for each center, one the center and the seconds a neighbor. lastly you can use geodesic component between centers and the closest neighbor to have curves on surface with the smallest possible length.

cheers

alex

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