Interactive Handling of a Construction Plan in CAD

Solving geometric metric constraints is a topical issue in CAD. An original way to solve a constraint system is to use geometric methods, providing a symbolic construction plan. Then, this plan can be numerically interpreted to generate the required figure. If multiple solutions are produced, most solvers propose to scan the entire space of the solutions found, that is generally tedious. This chapter shows how the inner properties of a symbolic solver allow to deal more efficiently with this case. After briefly recalling our sketch-based selection method, that enables to easily eliminate most of the solutions and to keep the only, or at the worst the few solutions that have the best likeness with the original drawing, we introduce a new step by step interpretation mechanism implemented as a debugger-like tool, that allows to browse the remaining solutions tree in order to help the user choosing the required solution.