C# "equalize" random points

by peter fotiadis

Sep 19, 2014

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

 

  • up

    Thomas

    Hi!

    Script 1:

    If I understand you correctly you have a list of points and you want to select the points where the shortest distance to all other points is within a given interval.

    A very simple attempt:

    The result might depend on the order of the points (first point -> higher priority).

    13

    Sep 19, 2014

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    • up

      Vicente Soler

      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>
      2

      Sep 21, 2014