Specify 3D Coordinates

Entering 3D world coordinate system (WCS) coordinates is similar to entering 2D WCS coordinates. In addition to specifying X and Y values, you specify a Z value. 2D coordinates are represented by a Point2d object, while you use a Point3d object to represent 3D coordinates. Most properties and methods in the .NET API utilize 3D coordinates.

For more information about specifying 3D coordinates, see “Enter 3D Coordinates” in the AutoCAD User's Guide.

Define and query the coordinates for 2D and 3D polylines

This example creates two polylines, each with three coordinates. The first polyline is a 2D polyline, the second polyline is 3D. Notice that the length of the array containing the vertices is expanded to include the Z coordinates in the creation of the 3D polyline. The example concludes by querying the coordinates of the polylines and displaying the coordinates in a message box.

VB.NET

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

Imports Autodesk.AutoCAD.Geometry

<CommandMethod("Polyline_2D_3D")> _

Public Sub Polyline_2D_3D()

  '' Get the current document and database, and start a transaction

  Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument

  Dim acCurDb As Database = acDoc.Database

  Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()

      '' Open the Block table for read

      Dim acBlkTbl As BlockTable

      acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, _

                                   OpenMode.ForRead)

      '' Open the Block table record Model space for write

      Dim acBlkTblRec As BlockTableRecord

      acBlkTblRec = acTrans.GetObject(acBlkTbl(BlockTableRecord.ModelSpace), _

                                      OpenMode.ForWrite)

      '' Create a polyline with two segments (3 points)

      Dim acPoly As Polyline = New Polyline()

      acPoly.AddVertexAt(0, New Point2d(1, 1), 0, 0, 0)

      acPoly.AddVertexAt(1, New Point2d(1, 2), 0, 0, 0)

      acPoly.AddVertexAt(2, New Point2d(2, 2), 0, 0, 0)

      acPoly.ColorIndex = 1

      '' Add the new object to the block table record and the transaction

      acBlkTblRec.AppendEntity(acPoly)

      acTrans.AddNewlyCreatedDBObject(acPoly, True)

      '' Create a 3D polyline with two segments (3 points)

      Dim acPoly3d As Polyline3d = New Polyline3d()

      acPoly3d.ColorIndex = 5

      '' Add the new object to the block table record and the transaction

      acBlkTblRec.AppendEntity(acPoly3d)

      acTrans.AddNewlyCreatedDBObject(acPoly3d, True)

      '' Before adding vertexes, the polyline must be in the drawing

      Dim acPts3dPoly As Point3dCollection = New Point3dCollection()

      acPts3dPoly.Add(New Point3d(1, 1, 0))

      acPts3dPoly.Add(New Point3d(2, 1, 0))

      acPts3dPoly.Add(New Point3d(2, 2, 0))

      For Each acPt3d As Point3d In acPts3dPoly

          Dim acPolVer3d As PolylineVertex3d = New PolylineVertex3d(acPt3d)

          acPoly3d.AppendVertex(acPolVer3d)

          acTrans.AddNewlyCreatedDBObject(acPolVer3d, True)

      Next

      '' Get the coordinates of the lightweight polyline

      Dim acPts2d As Point2dCollection = New Point2dCollection()

      For nCnt As Integer = 0 To acPoly.NumberOfVertices - 1

          acPts2d.Add(acPoly.GetPoint2dAt(nCnt))

      Next

      '' Get the coordinates of the 3D polyline

      Dim acPts3d As Point3dCollection = New Point3dCollection()

      For Each acObjIdVert As ObjectId In acPoly3d

          Dim acPolVer3d As PolylineVertex3d

          acPolVer3d = acTrans.GetObject(acObjIdVert, _

                                         OpenMode.ForRead)

          acPts3d.Add(acPolVer3d.Position)

      Next

      '' Display the Coordinates

      Application.ShowAlertDialog("2D polyline (red): " & vbLf & _

                                  acPts2d(0).ToString() & vbLf & _

                                  acPts2d(1).ToString() & vbLf & _

                                  acPts2d(2).ToString())

      Application.ShowAlertDialog("3D polyline (blue): " & vbLf & _

                                  acPts3d(0).ToString() & vbLf & _

                                  acPts3d(1).ToString() & vbLf & _

                                  acPts3d(2).ToString())

      '' Save the new objects to the database

      acTrans.Commit()

  End Using

End Sub

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.Geometry;

[CommandMethod("Polyline_2D_3D")]

public static void Polyline_2D_3D()

  // Get the current document and database, and start a transaction

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())

      // Open the Block table record for read

      BlockTable acBlkTbl;

      acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId,

                                   OpenMode.ForRead) as BlockTable;

      // Open the Block table record Model space for write

      BlockTableRecord acBlkTblRec;

      acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],

                                      OpenMode.ForWrite) as BlockTableRecord;

      // Create a polyline with two segments (3 points)

      Polyline acPoly = new Polyline();

      acPoly.AddVertexAt(0, new Point2d(1, 1), 0, 0, 0);

      acPoly.AddVertexAt(1, new Point2d(1, 2), 0, 0, 0);

      acPoly.AddVertexAt(2, new Point2d(2, 2), 0, 0, 0);

      acPoly.ColorIndex = 1;

      // Add the new object to the block table record and the transaction

      acBlkTblRec.AppendEntity(acPoly);

      acTrans.AddNewlyCreatedDBObject(acPoly, true);

      // Create a 3D polyline with two segments (3 points)

      Polyline3d acPoly3d = new Polyline3d();

      acPoly3d.ColorIndex = 5;

      // Add the new object to the block table record and the transaction

      acBlkTblRec.AppendEntity(acPoly3d);

      acTrans.AddNewlyCreatedDBObject(acPoly3d, true);

      // Before adding vertexes, the polyline must be in the drawing

      Point3dCollection acPts3dPoly = new Point3dCollection();

      acPts3dPoly.Add(new Point3d(1, 1, 0));

      acPts3dPoly.Add(new Point3d(2, 1, 0));

      acPts3dPoly.Add(new Point3d(2, 2, 0));

      foreach (Point3d acPt3d in acPts3dPoly)

          PolylineVertex3d acPolVer3d = new PolylineVertex3d(acPt3d);

          acPoly3d.AppendVertex(acPolVer3d);

          acTrans.AddNewlyCreatedDBObject(acPolVer3d, true);

      // Get the coordinates of the lightweight polyline

      Point2dCollection acPts2d = new Point2dCollection();

      for (int nCnt = 0; nCnt < acPoly.NumberOfVertices; nCnt++)

          acPts2d.Add(acPoly.GetPoint2dAt(nCnt));

      // Get the coordinates of the 3D polyline

      Point3dCollection acPts3d = new Point3dCollection();

      foreach (ObjectId acObjIdVert in acPoly3d)

          PolylineVertex3d acPolVer3d;

          acPolVer3d = acTrans.GetObject(acObjIdVert,

                                         OpenMode.ForRead) as PolylineVertex3d;

          acPts3d.Add(acPolVer3d.Position);

      // Display the Coordinates

      Application.ShowAlertDialog("2D polyline (red): \n" +

                                  acPts2d[0].ToString() + "\n" +

                                  acPts2d[1].ToString() + "\n" +

                                  acPts2d[2].ToString());

      Application.ShowAlertDialog("3D polyline (blue): \n" +

                                  acPts3d[0].ToString() + "\n" +

                                  acPts3d[1].ToString() + "\n" +

                                  acPts3d[2].ToString());

      // Save the new object to the database

      acTrans.Commit();

VBA/ActiveX Code Reference