virtual void UpdateDelta ( double InDeltaU, double InUSag, double InDiagonalSag, double InVSag, double ChordLength, double DiagonalLength, double & OutDeltaUMax, double & OutDeltaUMin, [FIsoCurvature](API\Runtime\CADKernel\CADKernel\Math\FIsoCurvature) & SurfaceCurvature ) const