Approaches researching and solution selecting of constrained-based geometric design

This paper reports two geometric constraint-solving approaches for the same constraint problems based on symbolic computation and constructive computation. The method of determining convexo and concave vertex can be employed to selecting multiple solutions generated in symbolic approach. We also make much concern about under-constrained and over-constrained problems, which make the computation more complex and unsmooth. Moreover, we present two decision methods to handle these problems before or during the acting of the constructive process.