Is there any way to create a surface or region by point3d array?

[zhongbo.wu]

I have a point3d array, and i should create a surface or region by them, but i faild:

-2717.21,-2745.87,-72135
-2717.21,-2745.87,-71835
-2662.88,-2661.92,-71835
-2662.88,-2661.92,-71847
-2711.78,-2737.47,-71854.2
-2711.78,-2737.47,-72115.8
-2662.88,-2661.92,-72123
-2662.88,-2661.92,-72135
-2717.21,-2745.87,-72135

First, i create eight lines by these point3d, the use Region.CreateFromCurves() to create region but faild, then i try to create the region in AutoCAD, but it's faild too and show me: Open objects must be coplanar.

Is there anybody can give me some help? thanks a lot!

[Keith.Brown]

You can create a region from any closed loop.  See this article.

https://knowledge.autodesk.com/search-result/caas/CloudHelp/cloudhelp/2015/ENU/AutoCAD-NET/files/GUI...

If your point array defines a closed loop, you can create a closed polyline from it and then create the region.

[zhongbo.wu]

I have try to draw a 3dpoly by these point3d in AutoCAD, then create region by this 3dpoly, but faild too with a message:1 closed, degenerate or unsupported object rejected.

[Alexander.Rivilis]

If points do not belong to the same plane it is impossible to create Region from those points.

[zhongbo.wu]

I know the points must belong to the same plane to create Region, but is there anyway to create a object like region or surface by these points? thanks a lot! 

[Alexander.Rivilis]

It is impossible create Region with this set of points.

I do not understand what can be done from this set of points in general. This set of points looks like a set of vertical bars.

[zhongbo.wu]

These data are come from another 3D software, in this software these points can create a polyhedron as shown below. So i'm try to create it in AutoCAD with these points:

[Alexander.Rivilis · Accepted solution]

@zhongbo.wu

Ok. As far as all points in your set is on one plane - it is possible to create Region.

using System;
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.EditorInput;

#pragma warning disable 0618

[assembly: CommandClass(typeof(CreateRegion.MyCommands))]

namespace CreateRegion
{
  public class MyCommands
  {
    [CommandMethod("CreateRegsFromPoints")]
    public void MyCommand() // This method can have any name
    {
      // Put your command code here
      Document doc = Application.DocumentManager.MdiActiveDocument;
      if (doc == null) return;
      Editor ed = doc.Editor;
      Point3dCollection pts = GetPoints();

      Plane plane = new Plane(pts[0], pts[1], pts[2]);

      for (int i = 0; i < pts.Count; i++)
      {
        pts[i] = pts[i].OrthoProject(plane);
      }

      ObjectId plineId = ObjectId.Null;
      using (Polyline pline = new Polyline())
      {
        pline.Normal = plane.Normal;
        Matrix3d mat = Matrix3d.PlaneToWorld(plane).Inverse();

        for (int i = 0; i < pts.Count; i++)
        {
          Point3d p = pts[i].TransformBy(mat);
          pline.AddVertexAt(i, new Point2d(p.X, p.Y), 0, 0, 0);
        }

        mat = Matrix3d.Displacement(pts[0] - pline.GetPoint3dAt(0));
        pline.TransformBy(mat);

        using (BlockTableRecord btr =
          doc.Database.CurrentSpaceId.Open(OpenMode.ForWrite) as BlockTableRecord)
        {
          // plineId = btr.AppendEntity(pline);
          DBObjectCollection objs = new DBObjectCollection();
          objs.Add(pline);
          DBObjectCollection regs = Region.CreateFromCurves(objs);

          if (regs != null)
          {
            for (int i = 0; i < regs.Count; i++)
            {
              using (regs[i])
              {
                Entity ent = regs[i] as Entity;
                if (ent != null)
                  btr.AppendEntity(ent);
              }
            }
          }
        }
      }
    }

    Point3dCollection GetPoints()
    {
      Point3dCollection pts = new Point3dCollection();
      pts.Add(new Point3d(-2717.21, -2745.87, -72135));
      pts.Add(new Point3d(-2717.21, -2745.87, -71835));
      pts.Add(new Point3d(-2662.88, -2661.92, -71835));
      pts.Add(new Point3d(-2662.88, -2661.92, -71847));
      pts.Add(new Point3d(-2711.78, -2737.47, -71854.2));
      pts.Add(new Point3d(-2711.78, -2737.47, -72115.8));
      pts.Add(new Point3d(-2662.88, -2661.92, -72123));
      pts.Add(new Point3d(-2662.88, -2661.92, -72135));
      pts.Add(new Point3d(-2717.21, -2745.87, -72135));
      return pts;
    }
  }
}

[zhongbo.wu]

Hi, Alex, thanks for your help, i get it!