var oRoot = Application.ActiveProject.ActiveScene.Root
// Create two cubes, first is the original and second is rotated
var oCube = oRoot.AddGeometry("Cube","MeshSurface", "Cube")     
var oCube2 = oRoot.AddGeometry("Cube","MeshSurface", "Cube2")   
var oTrans2 = oCube2.Kinematics.Local.Transform
var oMat3 = XSIMath.CreateMatrix3()
oTrans2.GetRotationMatrix3 ( oMat3 );
// Modify the matrix to rotate around z
oMat3.value(0,0) = Math.cos (45);
oMat3.value(0,1) = -Math.sin (45);
oMat3.value(1,1) = Math.cos (45);
oMat3.value(1,0) = Math.sin (45);
oTrans2.SetRotationFromMatrix3 ( oMat3 );       
oCube2.Kinematics.Local.Transform = oTrans2;
var vbArr = new VBArray( oMat3.Get2() );
var array = vbArr.toArray();
Application.LogMessage( "SIMatrix3 after the rotation" +
        " m00:" + array[0] + " m01:" + array[1] + " m02:" + array[2] + 
        " m10:" + array[3] + " m11:" + array[4] + " m12:" + array[5] + 
        " m20:" + array[6] + " m21:" + array[7] + " m22:" + array[8] );
// Expected results:
//INFO : SIMatrix3 after the rotation 
//              m00:0.5253219888177297  m01:-0.8509035245341184 m02:0 
//              m10:0.8509035245341184  m11:0.5253219888177297  m12:0 
//              m20:0                   m21:0                   m22:1