  Direct modeling is a very recent CAD paradigm that can provide unprecedented
modeling flexibility. It, however, lacks the parametric capability, which is
indispensable to modern CAD systems. For direct modeling to have this
capability, an additional associativity information layer in the form of
geometric constraint systems needs to be incorporated into direct modeling.
This is no trivial matter due to the possible inconsistencies between the
associativity information and geometry information in a model after direct
edits. The major issue of resolving such inconsistencies is that there often
exist many resolution options. The challenge lies in avoiding invalid
resolution options and prioritizing valid ones. This paper presents an
effective method to support the user in making decisions among the resolution
options. In particular, the method can provide automatic information
inconsistency reasoning, avoid invalid resolution options completely, and guide
the choice among valid resolution options. Case studies and comparisons have
been conducted to demonstrate the effectiveness of the method.

Computational Geometry;Graphics