internal static CoordinateSystem AtParameterCore(Surface contextSurface, double u, double v, bool visible) { if (contextSurface == null) throw new System.ArgumentNullException("contextSurface"); var cs = contextSurface.GetCSAtParameters(u, v); if (null == cs) throw new System.Exception(string.Format(Properties.Resources.OperationFailed, "CoordinateSystem.AtParameter")); cs.ContextSurface = contextSurface; cs.U = u; cs.V = v; cs.Visible = visible; return cs; }