Research Of Triangle Mesh Model Data Processing Technology Based On Mixed Blend Feature In Reverse Engineering

Triangular mesh model possesses the simple and intuitive characteristics,whichmakes it the most popular format of model shows.Feature reconstruction is widelyused in reverse engineering model reconstruction process,for it can faces bothdesign and manufacturing process. Feature has very important control effect ofgeometrical shape of products, thus feature treatment technologies are the keyfield technology in reverse engineering, and the core part is feature extractiontechnique because this process is the foundation and prerequisite of follow-upprocessing. As the blend features especially mixed blend feature can not beextracted effectively by using single vector or curvature information, therefore, theblend feature extraction technology is a hotspot and quite difficult in currentresearch.According to irregularities and topological structure of mixed blend feature intriangular mesh model, this paper presents a new multi threshold of vector anglefeature extraction algorithm to hybrid blend feature extraction. Firstly，mixedblend feature is extracted by a group threshold angles of normal vector which cansegment the model preliminary, and point set with different threshold angles ofeach non-feature region are determined; then each region least-square fittingprecision of different threshold angles are compared in order to choose the bestthreshold angle of normal vector;Finally, mixed blend features are extractedaccurately by the best threshold angle of different regions, in this way trianglemesh model segmentation based on features is taken out.An improved space mesh growing hole filling algorithm is proposed aiming attriangular mesh holes in mixed blend feature region and cross regions. Firstly, allboundary feature is recognized and hole boundaries are automaticly identified byhole boundary properties; then the hole area is filled by meshes through spatialmesh growth method; finally, new added vertex positions are adjusted byleast-square method according to the boundary area vertex. Introducing region segmentation and boundary features curve fitted into mixed blend feature andcross regions hole filling algorithm, provides a feasible scheme for improvingfilling precision in multi-regions hole filling problem.For the purpose of feature regions protection in triangular mesh simplificationprocess, a mesh simplification algorithm based on region segmentation is adopted.According to the needs of simplification, regions simplified quantity distributionsare rationally adjusted by region mesh quantity ratios and region curvature values,and as a result, the simplified quantities of feature regions with large curvature arereduced. Each region is simplified independently by a QEM model simplificationalgorithm with added area weights of relevant triangle meshes; realize effectivelyfeature region protection in the triangle mesh model simplification processing."Processing prototype system based on mixed blend features of3D modelreconstruction" is constructed based on above studies.This system can transfereach algorithm into visualization in correlation model processing process.