C# Surface.ShortPath function in a 3D model

Dear all,

I'm getting more and more familiar with the C# scripting, but I've run into a problem for which I can't find the solution.

In my model I want to work with geodesic lines on a surface between it's borders. Grasshopper has a Geodesic-component which can do that, but now I want to use it in a loop-script in C#. For this, I found the ShortPath function which you earlier talked about in another discussion:

http://www.grasshopper3d.com/forum/topics/is-there-a-way-to-measure...

The question: How do I use and control the 3D-Points in my model, when it asks for a 2d-Point for the ShortPath? Or is there an other/easier solution which I haven't found yet?

I've attached a gh-model with a simplified version of my model with the use of the Geodesic-component as an example and the part of the C#-script to the point where I want to make the geodesic line.

Thank you.

Joey

Attachments:

ShortPath script.gh, 15 KB

Replies to This Discussion

Permalink Reply by David Rutten on April 1, 2016 at 3:40am

ShortPath requires UV coordinates, not XYZ coordinates because (a) an xyz point might not be on the surface at all, and (b) an xyz coordinate might be at a place where the surface self-intersects or at a surface seam, in which case it's unclear exactly where the geodesic should start.

//Points to connect
Point3d p = new Point3d();
p = AB.PointAt(parAB);

Point3d q = new Point3d();
q = CD.PointAt(parCD);

double pu, pv;
surface.ClosestPoint(p, out pu, out pv);
Point2d puv = new Point2d(pu, pv);

double qu, qv;
surface.ClosestPoint(q, out qu, out qv);
Point2d quv = new Point2d(qu, qv);

//Geodesic connection
Curve geo = surface.ShortPath(puv, quv, 0.1);

//Output
P = p;
Q = q;
Geodesic = geo;

Permalink Reply by Joey janssen on April 1, 2016 at 3:49am