C# "equalize" random points

Well friends,

Imagine a brep with a single face (a trimmed surface) that "approximates" some tensile membrane that may look like this image attached (prior sending stuff to Kangaroo). Not my project: in fact some friend's friend asked that in order to send a collection of random "anchor" points to Kangaroo and ... blah blah.

The requirement is to find anchor points by (a) creating a random set of points (within the projected face in a given plane, in most of cases the global xy) and then (b) "culling" them as follows:

(b.1) no two points are closer than MinDistance.

(b.2) no two points are too far away than MinDistance.

... and then (c) project them on a mesh (derived from the brep)

So this script attempts to "cull" randomly placed points that satisfy(?) the MinMax criteria and do the rest. NOTE: points are few ... so don't stick to algorithm's efficiency.

2 questions for the willing gurus out there:

Script 1: this "cull" approach is rather wrong - I'm open to any suggestion.

Script 2: change the MaxDist value and observe the script turning from red to OK status. Why?

NOTE: GH fails to internalize stuff quite frequently. If this is the case, use Rhino file

best, Peter

Attachments:

projectpointsonmesh3.gh, 370 KB
projectpointsonmesh.3dm, 412 KB

Replies to This Discussion

Permalink Reply by Thomas on September 21, 2014 at 11:05am

That one

Permalink Reply by peter fotiadis on September 22, 2014 at 1:05am

Guideline for resolving all things: (a) set mode to sport, (b) ride

Attachments:

projectpointsonmesh6.gh, 458 KB
projectpointsonmesh6.3dm, 579 KB

Permalink Reply by Vicente Soler on September 21, 2014 at 6:01am

If you reference the Vector.gha assembly in a scripting component you can use the PopulationSolver class that is used in the Populate components. You'll have to create a derived class that inherits it.

(I don't know if I'm breaking the user agreement doing this.)

Sample code for a C# scripting component:

private void RunScript(object x, object y, ref object A)
{
    var rectangle = new Rectangle3d(Plane.WorldXY, 10, 10);
    int numPoints = 100;
    int seed = 24601;
    var existingPts = new List <Point3d>();
 
    var rectangleSolver = new RectangleSolver(rectangle, seed);
    A = rectangleSolver.Populate(numPoints, existingPts);
 
}
 
// <Custom additional code> 
public class RectangleSolver : PopulationSolver
{
    Rectangle3d rectangle;
    public RectangleSolver(Rectangle3d rectangle, int seed)
        : base(seed)
    {
        this.rectangle = rectangle;
    }
    protected override BoundingBox BoundingBox()
    {
        return this.rectangle.BoundingBox;
    }
    protected override Point3d NextPoint()
    {
        return this.rectangle.PointAt(this.RandomNumber(), this.RandomNumber());
    }
}
// </Custom additional code>

Permalink Reply by David Rutten on September 21, 2014 at 6:42am

This is not a violation of the license agreement, you are allowed to reference any assembly that ships with Grasshopper and use the methods provided therein.

Permalink Reply by Vicente Soler on September 21, 2014 at 6:50am

Yes, although I used a reflector to find the class and see how it was implemented.

In this case the implementation was pretty trivial, so hopefully it doesn't count as copy-pasting the code of a private class.