Constraint-based parametric description and inferring is one of the host spot in the research of computer-aided design

the solution to under constraint graph is a basic question in parametric design

this paper presents a series of solving methods for sketch drawing based on the priority of under constraint. This article gives general methods for under constraint graph and its basic features firstly

a new method for the solution to under constraint graph in sketch drawing is put forward

in which required apparent constraints are replaced by concealed constraints. The directed process of constraint graph is completed by picking concealed constraints of adjacent entities in sketch of few or no dimensions. In this paper

the priority of concealed constraint is given by the different constraint types and constructing orders

and some more priority concealed constraints are forced into obvious ones by the need number of constraint for every node in constraint solution process.