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.

直接建模是最新的CAD范例，可以提供前所未有的建模灵活性。但是，它缺乏参数功能，这是现代CAD系统必不可少的。为了使直接建模具有此功能，需要将几何约束系统形式的附加关联性信息层合并到直接建模中。由于直接编辑后模型中的关联性信息和几何信息之间可能存在不一致，因此这并不是一件容易的事。解决此类不一致的主要问题是，通常存在许多解决方案。挑战在于避免无效的解决方案选项，并对有效选项进行优先排序。本文提出了一种有效的方法来支持用户在分辨率选项中做出决策。尤其是，该方法可以提供自动的信息不一致推理，完全避免无效的解决方案选项，并指导有效的解决方案选项之间的选择。已经进行了案例研究和比较，以证明该方法的有效性。