Research On Simplification And Repair Of 3D Mesh Based On OpenMesh

With the rapid development of 3D information acquisition equipment and 3D simulation scene technology,3D model has become an important data structure and has been widely used in 3D games,animation,virtual scene simulation,cultural relics protection and so on.The more realistic the display effect of the model is,the finer the model is,but it means that it contains a large number of triangular patches,which brings great pressure to the storage,calculation and visual rendering of the computer.In the actual large-scale simulation scene,we do not need such a high-precision mesh model,but pay more attention to the continuity of beat.Therefore,it is necessary to simplify the three-dimensional model.When simplifying the CAD model,holes are easy to appear.At the same time,when the instrument collects data,due to the defects of the object to be measured and the limitations of the data acquisition equipment,the original data of the collected point cloud model is incomplete and holes will also appear.Therefore,it is necessary to repair the holes to keep the model complete and available.It makes an in-depth research from two aspects: mesh model simplification and hole repair,and verifies the effectiveness of the method proposed in this paper through comparative analysis experiments.The main research work of this paper includes the following aspects:(1)The 3D mesh processing framework is constructed.This paper analyzes the simplification process of QEM edge folding algorithm and the repair process of hole repair algorithm,analyzes its existing problems and requirements,and constructs the optimization processing system framework of three-dimensional point grid model.(2)Research on QEM edge folding optimization algorithm based on OpenMesh.When the edge folding algorithm for QEM is simplified,the detailed features of the model are easy to be lost,and the problems of ray and radiation surface are easy to appear when the CAD model is simplified.This paper proposes a QEM edge folding optimization algorithm based on OpenMesh.On the basis of QEM algorithm,the position of new folding points is judged,and the new points too far from the folding edge are limited to the folding edge to avoid the extreme situation of rays and radiation surfaces.Then add the influence factors such as the regularity of the edge connecting surface,the included angle of the edge connecting surface,the area of the edge connecting surface and whether it is a boundary edge,and process the data of the influence factors to better maintain the detailed characteristics of the model and improve the quality of the triangular mesh of the simplified model.(3)Research on mesh model patching optimization algorithm based on OpenMesh.In view of the common hole repair algorithms,when repairing multi hole models,it is difficult to associate two independent holes and determine the repair order,when repairing continuous sets of holes with complex types and structures,there is no unified and complete repair scheme,it is almost impossible to repair models with non hole boundaries,and the generated hole mesh is too unnatural with the surrounding mesh,This paper presents a repair optimization algorithm based on OpenMesh model.In this scheme,half edges are connected orderly.When the end point of the next edge is equal to the starting point of the first half,it is determined to form a closed hole polygon to extract a single hole polygon.Based on the idea of first in first out(FIFO)method,the repair problem of multi hole polygon is transformed into single hole repair.According to one belt,one road,the problem of repairing continuous polygon polygons is transformed into the restoration of polygonal polygons.At the same time,the method of retaining the hole boundary edge of CAD model and ignoring the non hole boundary edge is used to repair the hole boundary of CAD model.Finally,the repaired model is smoothed to improve the repair effect of the model and the quality of triangular mesh.(4)Implementation of 3D mesh model optimization processing system.Based on the above research,this paper integrates QT framework,OpenMesh,Open GL and other graphics development libraries on the platform of Visual Studio 2019,and independently develops a set of optimization processing system for 3D mesh model using C++ language,which realizes the model optimization scheme integrating the functions of model simplification,repair,smoothing and hole generation.Taking some representative grid models as examples,the specific application of the system is introduced,and the feasibility of the above method is verified.