Generating refinement control grid for generating smooth curved surface of object

Methods, systems, and apparatus for computer program products, including medium coding, for computer-aided design of structures include, in one aspect, a method for generation comprising: obtaining a polygonal control mesh representing a smooth curved surface of an object; subdividing the polygonal control mesh in one or more subdivisions to produce a refined control mesh, where the subdivision comprises: generating an adjustment rule using data defining a feature polyhedron around singular points in the polygonal control mesh to determine the singular points, according to the singular points and the positions of the face points and the edge points of the faces adjacent to the singular points, determining the singular points and the positions of the face points and the edge points of the faces adjacent to the singular points according to the adjustment rule; and generating, by the computer graphics application, the smooth curved surface for output from the refined control grid. 用于结构的计算机辅助设计的包括介质编码的计算机程序产品的方法、