Rotate Objects (.NET)

You can rotate all drawing objects and attribute reference objects.

To rotate an object, use the Rotation function of a transformation matrix. This function requires a rotation angle represented in radians, an axis of rotation, and a base point. The axis of rotation must be expressed as a Vector3d object and the base point as a Point3d object. This angle determines how far an object rotates around the base point relative to its current location.

Rotate a polyline about a base point

This example creates a closed lightweight polyline, and then rotates the polyline 45 degrees about the base point (4, 4.25, 0).

VB.NET

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
 
<CommandMethod("RotateObject")> _
Public Sub RotateObject()
    '' 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)

        '' Create a lightweight polyline
        Using acPoly As Polyline = New Polyline()
            acPoly.AddVertexAt(0, New Point2d(1, 2), 0, 0, 0)
            acPoly.AddVertexAt(1, New Point2d(1, 3), 0, 0, 0)
            acPoly.AddVertexAt(2, New Point2d(2, 3), 0, 0, 0)
            acPoly.AddVertexAt(3, New Point2d(3, 3), 0, 0, 0)
            acPoly.AddVertexAt(4, New Point2d(4, 4), 0, 0, 0)
            acPoly.AddVertexAt(5, New Point2d(4, 2), 0, 0, 0)

            '' Close the polyline
            acPoly.Closed = True

            Dim curUCSMatrix As Matrix3d = acDoc.Editor.CurrentUserCoordinateSystem
            Dim curUCS As CoordinateSystem3d = curUCSMatrix.CoordinateSystem3d

            '' Rotate the polyline 45 degrees, around the Z-axis of the current UCS
            '' using a base point of (4,4.25,0)
            acPoly.TransformBy(Matrix3d.Rotation(0.7854, _
                                                 curUCS.Zaxis, _
                                                 New Point3d(4, 4.25, 0)))

            '' Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acPoly)
            acTrans.AddNewlyCreatedDBObject(acPoly, True)
        End Using

        '' Save the new objects to the database
        acTrans.Commit()
    End Using
End Sub

C#

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
 
[CommandMethod("RotateObject")]
public static void RotateObject()
{
    // 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;

        // Create a lightweight polyline
        using (Polyline acPoly = new Polyline())
        {
            acPoly.AddVertexAt(0, new Point2d(1, 2), 0, 0, 0);
            acPoly.AddVertexAt(1, new Point2d(1, 3), 0, 0, 0);
            acPoly.AddVertexAt(2, new Point2d(2, 3), 0, 0, 0);
            acPoly.AddVertexAt(3, new Point2d(3, 3), 0, 0, 0);
            acPoly.AddVertexAt(4, new Point2d(4, 4), 0, 0, 0);
            acPoly.AddVertexAt(5, new Point2d(4, 2), 0, 0, 0);

            // Close the polyline
            acPoly.Closed = true;

            Matrix3d curUCSMatrix = acDoc.Editor.CurrentUserCoordinateSystem;
            CoordinateSystem3d curUCS = curUCSMatrix.CoordinateSystem3d;

            // Rotate the polyline 45 degrees, around the Z-axis of the current UCS
            // using a base point of (4,4.25,0)
            acPoly.TransformBy(Matrix3d.Rotation(0.7854,
                                                 curUCS.Zaxis,
                                                 new Point3d(4, 4.25, 0)));

            // Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acPoly);
            acTrans.AddNewlyCreatedDBObject(acPoly, true);
        }

        // Save the new objects to the database
        acTrans.Commit();
    }
}

VBA/ActiveX Code Reference

Sub RotateObject()
    ' Create the polyline
    Dim plineObj As AcadLWPolyline
    Dim points(0 To 11) As Double
    points(0) = 1: points(1) = 2
    points(2) = 1: points(3) = 3
    points(4) = 2: points(5) = 3
    points(6) = 3: points(7) = 3
    points(8) = 4: points(9) = 4
    points(10) = 4: points(11) = 2
    Set plineObj = ThisDrawing.ModelSpace. _
                                    AddLightWeightPolyline(points)
    plineObj.Closed = True
    ZoomAll
 
    ' Define the rotation of 45 degrees about a
    ' base point of (4, 4.25, 0)
    Dim basePoint(0 To 2) As Double
    Dim rotationAngle As Double
    basePoint(0) = 4: basePoint(1) = 4.25: basePoint(2) = 0
    rotationAngle = 0.7853981   ' 45 degrees
 
    ' Rotate the polyline
    plineObj.Rotate basePoint, rotationAngle
    plineObj.Update
End Sub