Research On The Approach To CAD Mesh Model Segmentation

Currently 3D mesh model has been a main representation of 3D solid models, which makes reuse of existing mesh model according to the design requirement a significant challenge. Mesh segmentation, which is proposed to solve the problem, has become a hot research topic in CAD&CG. In order to enable it, this thesis mainly researches on the approach to the CAD mesh model segmentation.An approach to CAD mesh segmentation is proposed to meet the requirements of engineering applications. The approach has four major parts: addition of vertices, improved watershed with multiple direction descent, iterative region merging and post process such as boundary refinement. Traditional watershed algorithm is improved by using multiple descent strategy and reconstruction of region information based on triangle's region label. No hard boundary problem, which is the main drawback of the traditional watershed, is settled by adopting improved watershed algorithm to partition meshes.An addition of vertices method to CAD mesh model is used to solve the problem that watershed algorithm couldn't handle the meshes with non-uniform triangulation. By adaptively adding points, the triangulation of CAD meshes is improved effectively. A novel iterative region merging algorithm is presented to support the partition for blending surfaces which are widely spread in CAD models.Finally, a CAD mesh model segmentation prototype system is implemented and is soon used in the CAD mesh simplification system which is based on engineering feature suppression. Several complex CAD mesh models are used to test the approach, and the validity is certified.