The increase of optical resolution and size of astronomical telescopes needs to: (1) Improve surface quality of optical components. (2) Use more and more complex aspherical shape for lenses and mirrors. Due to these 2 constraints, the optical manufacturers had to improve theirs equipments such as the Computer Controlled Polishing and to appreciate the feasibility of very complex aspherical shape. Concerning this second point, we propose a new criterion based on surface definition, on quality specification for the polishing and on limitations of equipments. Manufacturing examples show that this criterion is well representative, and particularly for direct off-axis polishing.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.