topic Re: Problem using intersectWith in .NET Forum

Problem using intersectWith

Anonymous — Fri, 24 Mar 2017 09:08:53 GMT

my code

 [CommandMethod("testLineCross")]
  public void testLineCross()
 {
             Document doc = AcadApp.DocumentManager.MdiActiveDocument;
             Editor ed = doc.Editor;
             Database db = doc.Database;
             PromptEntityResult per = ed.GetEntity("Line1");
             using (Transaction tr = doc.TransactionManager.StartOpenCloseTransaction())
             {
                 Line l1 = tr.GetObject(per.ObjectId, OpenMode.ForRead) as Line;
                 per = ed.GetEntity("Line2");
                 Line l2 = tr.GetObject(per.ObjectId, OpenMode.ForRead) as Line;
                 Point3dCollection ptcol = new Point3dCollection();
                 l1.IntersectWith(l2, Intersect.ExtendBoth,ptcol, IntPtr.Zero, IntPtr.Zero);
                 if (ptcol.Count > 0)
                     ed.WriteMessage("Intersect");
                 else
                     ed.WriteMessage("non-intersect");
                 tr.Commit();
             }	
   }

My dwg see the Attachemnts.

why get the intersectPoint?

Version:AutoCAD 2012

Re: Problem using intersectWith

Anonymous — Fri, 24 Mar 2017 12:26:24 GMT

Line1
                 from， X=11924.7823 Y=8634.7220 Z=   0.0000
                to， X=11926.0027 Y=-9044.7187 Z=   0.0000
Line2
                from， X=5170.8647 Y=2737.5595 Z=   0.0000
                 to， X=18677.5784 Y=2737.5595 Z=   0.0000

using the code:

 l1.IntersectWith(l2, Intersect.ExtendBoth,ptcol, IntPtr.Zero, IntPtr.Zero);

but the resulst show ptcol.Count==0.Why can not get the intersect point?

Re: Problem using intersectWith

Alexander.Rivilis — Fri, 24 Mar 2017 13:03:41 GMT

It easy explain:

Re: Problem using intersectWith

Anonymous — Fri, 24 Mar 2017 13:07:36 GMT

thank you.

how to avoid this precision error?

Convert to 2D Line?

Re: Problem using intersectWith

Alexander.Rivilis — Fri, 24 Mar 2017 13:08:02 GMT

I can recommend using this method:

public void IntersectWith(
    Entity entityPointer, 
    Autodesk.AutoCAD.DatabaseServices.Intersect intersectType, 
    Plane projectionPlane, // !!!!!!!! 
    Point3dCollection points, 
    IntPtr thisGraphicSystemMarker, 
    IntPtr otherGraphicSystemMarker
);

Re: Problem using intersectWith

Richard_AshJNQQ8 — Fri, 15 Mar 2024 05:07:57 GMT

Thanks for the help 🙂