1. A method of producing BREP data from electronic polygonal data, the method comprising: accessing the polygonal data with a computer, the polygonal data defining a mesh of polygonal data points; generating a plurality of continuous curves based on the polygonal data; based at least in part on the continuous curves, generating a plurality of surface boundaries defining one or more continuous surfaces; generating the BREP data based at least in part on the continuous surfaces; and storing the BREP data in a computer readable data storage.