public StaticPlaneShape AddStaticPlaneShape(float3 planeNormal, float planeConstant)
        {
            IStaticPlaneShapeImp iStaticPlaneShapeImp = _dwi.AddStaticPlaneShape(planeNormal, planeConstant);
            var retval = new StaticPlaneShape();

            retval._staticPlaneShapeImp     = iStaticPlaneShapeImp;
            iStaticPlaneShapeImp.UserObject = retval;
            return(retval);
        }