Can anyone tell me what I'm doing wrong? It returns only the X coordinate, Y and Z return zero "0".

       internal void TransformPoints(SketchPoint sp)
        {
            try
            {
                MathUtility swMathUtil = (MathUtility)_swApp.GetMathUtility();
                double[] cPT = { sp.X, sp.Y, sp.Z };
                double[] vPoint = null;
                MathPoint swMathPt2 = default(MathPoint);
                swMathPt2 = (MathPoint)swMathUtil.CreatePoint(cPT);
                swMathPt2 = (MathPoint)swMathPt2.MultiplyTransform(sp.GetSketch().ModelToSketchTransform.Inverse());
                vPoint = (double[])swMathPt2.ArrayData;
            }
            catch (Exception ex)
            {
            }
        }