将零件进行特征基元体分解,通过分析基元体在组合成为零件时尺寸功能语义的变化来生成尺寸模型。利用单个基元体的特征元素和消失元素确定初始定形尺寸,利用基元体组合时刚体自由度完备约束条件和尺寸约束定位作用,生成初始定位尺寸。针对基元体在组合时因特殊结构和组合方法不同而发生尺寸变异的情况,分别提出消失尺寸、新生尺寸和转换尺寸三种处理方法。消失尺寸和新生尺寸用于确定尺寸数量和尺寸约束元素,转换尺寸用于解决尺寸视图安排问题,从而得到最终的尺寸模型。实例表明,开发的原型系统模型是有效的。
Disassembling a part into the features of basic entity(FBE), the dimensional models were gained by analyzing the change of the functional semantics of dimension during FEE's combination. Original shaping dimensions can be got by recognition the of FBE~s feature elements and disappearing elements. Through analyzing the integrity of rigid body's freedom degree and the locating effect of dimension constraint, original locating dimensions were also acquired. According to the dimensional variance during combination because of special structure and combination way, three dimensions including disappearing dimension, fresh dimension, converted dimension were put forward. The number and constrained elements of dimension can be fixed by disappearing dimension and fresh dimension, so with the assignment of dimension in 2D view by converted dimension. Therefore the ultimate dimension models were advanced. An example is given by the software prototype realizing the dimensional model and the result is persuasive.