Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

Imports Autodesk.AutoCAD.Geometry

<CommandMethod("AddSpline")> _

Public Sub AddSpline()

  '' Get the current document and database

  Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument

  Dim acCurDb As Database = acDoc.Database

  '' Start a transaction

  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)

      '' Define the fit points for the spline

      Dim ptColl As Point3dCollection = New Point3dCollection()

      ptColl.Add(New Point3d(0, 0, 0))

      ptColl.Add(New Point3d(5, 5, 0))

      ptColl.Add(New Point3d(10, 0, 0))

      '' Get a 3D vector from the point (0.5,0.5,0)

      Dim vecTan As Vector3d = New Point3d(0.5, 0.5, 0).GetAsVector

      '' Create a spline through (0, 0, 0), (5, 5, 0), and (10, 0, 0) with a

      '' start and end tangency of (0.5, 0.5, 0.0)

      Dim acSpline As Spline = New Spline(ptColl, vecTan, vecTan, 4, 0.0)

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

      acBlkTblRec.AppendEntity(acSpline)

      acTrans.AddNewlyCreatedDBObject(acSpline, True)

      '' Save the new object 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("AddSpline")]

public static void AddSpline()

{

  // Get the current document and database

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  // Start a transaction

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

  {

      // Open the Block table 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;

      // Define the fit points for the spline

      Point3dCollection ptColl = new Point3dCollection();

      ptColl.Add(new Point3d(0, 0, 0));

      ptColl.Add(new Point3d(5, 5, 0));

      ptColl.Add(new Point3d(10, 0, 0));

      // Get a 3D vector from the point (0.5,0.5,0)

      Vector3d vecTan = new Point3d(0.5, 0.5, 0).GetAsVector();

      // Create a spline through (0, 0, 0), (5, 5, 0), and (10, 0, 0) with a

      // start and end tangency of (0.5, 0.5, 0.0)

      Spline acSpline = new Spline(ptColl, vecTan, vecTan, 4, 0.0);

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

      acBlkTblRec.AppendEntity(acSpline);

      acTrans.AddNewlyCreatedDBObject(acSpline, true);

      // Save the new line to the database

      acTrans.Commit();

  }

}