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 AutoCAD .NET API utilize 3D coordinates.
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.
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)
Using 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)
Using 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
Using acPolVer3d As PolylineVertex3d = New PolylineVertex3d(acPt3d)
acPoly3d.AppendVertex(acPolVer3d)
acTrans.AddNewlyCreatedDBObject(acPolVer3d, True)
End Using
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())
End Using
End Using
'' 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)
using (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)
using (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)
{
using (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();
}
}
Sub Polyline_2D_3D()
Dim pline2DObj As AcadLWPolyline
Dim pline3DObj As AcadPolyline
Dim points2D(0 To 5) As Double
Dim points3D(0 To 8) As Double
' Define three 2D polyline points
points2D(0) = 1: points2D(1) = 1
points2D(2) = 1: points2D(3) = 2
points2D(4) = 2: points2D(5) = 2
' Define three 3D polyline points
points3D(0) = 1: points3D(1) = 1: points3D(2) = 0
points3D(3) = 2: points3D(4) = 1: points3D(5) = 0
points3D(6) = 2: points3D(7) = 2: points3D(8) = 0
' Create the 2D light weight Polyline
Set pline2DObj = ThisDrawing.ModelSpace. _
AddLightWeightPolyline(points2D)
pline2DObj.Color = acRed
pline2DObj.Update
' Create the 3D polyline
Set pline3DObj = ThisDrawing.ModelSpace. _
AddPolyline(points3D)
pline3DObj.Color = acBlue
pline3DObj.Update
' Query the coordinates of the polylines
Dim get2Dpts As Variant
Dim get3Dpts As Variant
get2Dpts = pline2DObj.Coordinates
get3Dpts = pline3DObj.Coordinates
' Display the coordinates
MsgBox ("2D polyline (red): " & vbCrLf & "(" & _
get2Dpts(0) & ", " & get2Dpts(1) & ")" & vbCrLf & "(" & _
get2Dpts(2) & ", " & get2Dpts(3) & ")"& vbCrLf & "(" & _
get2Dpts(4) & ", " & get2Dpts(5) & ")")
MsgBox ("3D polyline (blue): " & vbCrLf & "(" & _
get3Dpts(0) & ", " & get3Dpts(1) & ", " & _
get3Dpts(2) & ")" & vbCrLf & "(" & _
get3Dpts(3) & ", " & get3Dpts(4) & ", " & _
get3Dpts(5) & ")" & vbCrLf & "(" & _
get3Dpts(6) & ", " & get3Dpts(7) & ", " & _
get3Dpts(8) & ")")
End Sub