.NET

[#1]

Hi pro,

Please let me know how to offset a opened polyline by pick point on side of opened polyline.

Thanks,

[#2 · Accepted solution]

With minimum error checking. Only as idea.

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

[assembly: CommandClass(typeof(Rivilis.CurveUtils))]

namespace Rivilis
{
  public class CurveUtils
  {
    [CommandMethod("OffsetCurve", CommandFlags.Modal)]
    public static void OffsetCurve()
    {
      Document doc = Application.DocumentManager.MdiActiveDocument;
      Editor ed = doc.Editor;
      PromptDoubleResult resValueOff = ed.GetDistance("\nOffset value: ");
      if (resValueOff.Status != PromptStatus.OK) return;
      PromptPointResult  resPointOff = ed.GetPoint("\nOffset side: ");
      if (resPointOff.Status != PromptStatus.OK) return;
      PromptEntityOptions prCurv = new PromptEntityOptions("\nSelect curve: ");
      prCurv.SetRejectMessage("not a Curve");
      prCurv.AddAllowedClass(typeof(Curve),false);
      PromptEntityResult resCurv = ed.GetEntity(prCurv);
      if (resCurv.Status != PromptStatus.OK) return;
      
      using  (Transaction tr = doc.TransactionManager.StartTransaction()) {
        Curve curve = tr.GetObject(resCurv.ObjectId, OpenMode.ForRead) as Curve;
        if (curve != null) {
          BlockTableRecord btr = tr.GetObject(curve.BlockId, OpenMode.ForWrite) as BlockTableRecord;
          if (btr != null) {
            Point3d pDir = (Point3d)(Application.GetSystemVariable("VIEWDIR"));
            if (pDir != null) {
              Point3d pWCS = resPointOff.Value.TransformBy(ed.CurrentUserCoordinateSystem);
              double offset = IsRightDirection(curve, pWCS, pDir.GetAsVector()) ? resValueOff.Value : -resValueOff.Value;
              DBObjectCollection curvCols = curve.GetOffsetCurves(offset);
              foreach (DBObject obj in curvCols) {
                Curve subCurv = obj as Curve;
                if (subCurv != null) {
                  btr.AppendEntity(subCurv);
                  tr.AddNewlyCreatedDBObject(subCurv, true);
                }
              }
            }
          }
        }
        tr.Commit();
      }
    }
    // Detect side of point
    public static bool IsRightDirection(Curve pCurv, Point3d p, Vector3d vDir)
    {
      Vector3d vNormal = Vector3d.ZAxis;
      if (pCurv.IsPlanar) {
        Plane plane = pCurv.GetPlane();
        vNormal = plane.Normal;
        p = p.Project(plane, vDir);
      }
      Point3d pNear = pCurv.GetClosestPointTo(p, true);
      Vector3d vSide = p - pNear;
      Vector3d vDeriv = pCurv.GetFirstDerivative(pNear);
      if (vNormal.CrossProduct(vDeriv).DotProduct(vSide) < 0.0)
        return true;
      else
        return false;
    }
  }
}

[#3]

Nice solution

Hats off

Cheers

[#4]

Great.It worked OK.

Thank Rivilis,