Automatic dimensioning of 3D model based on GB/T 24734

To meet the requirements of manufacturing enterprises, the automatic dimensioning of 3D model in CAD system was investigated based on the national standard GB/T 24734. The algorithms of automatic dimensioning of 3D model were proposed, and the strategies of datum recognition, features simplification, surfaces grouping, vertical projection and features restoration were described in detail. Currently, the processes of features simplification and restoration mainly deal with the blending, chamfering and array operations in both feature and cross-section levels. To make the layout and identification of dimensions much easier, the methods of surface grouping and vertical projection were applied to discompose the part. All the algorithms presented were realized and a module of automatic dimensioning was developed based on CAXA Solid. Case study shows that the strategies presented are feasible.