Research On The Technology Of 3D Intelligent Dimension Based On Feature-Constraint

CAD (Computer Aided Design) technologies have made a great progresses, and been used more and more widely. However, most of current dimensioning methods depend on man-made interaction with low intelligence and standardization, so it has limited application of CAD technologies mostly. In the paper, a new method combining feature modeling with feature recognition is applied to the dimension of 3-D model, which improves efficiency and standardization of dimension. The main woks in the paper are as follows: Firstly, feature modeling technology, feature recognition technology and feature extraction technology are studies in the paper. A cell disassembling technology is used to obtain part feature, and a data structure of feature is defined by Object-Oriented technology. Secondly, through analyzed constraint relation between feature (and in feature) produced in process of feature modeling, the size dimension model and location dimension model based on feature constraint are constructed according to geometry dimension characteristic. Finally, the methods of creating size dimension model and location dimension model, and the strategy of adjusting dimension are studies in the paper. According to the above results, a 3D smart-dimensioning module based on feature constraint, which realizes an intelligent dimension for part primarily, is developed on CAXA solid design platform and has been used in a special computer-aided fixture design system.