Surface Smoothing And Blend Surface Constructing Methods With Its Application

With the rapid development of CAD/CAM, people bring forward higher requests to theproduct geometric design. Surface smoothing and blend surface constructing for the productgeometric design has been received great attention and extensive research, which has becomea research hotspot. This paper mainly focused on the grid surface smoothing algorithm andblend surface constructing method and its application in virtual orthodontics treatmentsystem.On the basis of analysis of the traditional grid smoothing algorithm, a new algorithmbased on the feature regions is studied and realized in this paper. Firstly, the grid model isdivided into the non-characteristic and characteristic feature regions according to thevariation of the normal. Secondly, the normal vector of triangular mesh is adjusted byLaplacian and combining bilateral filtering in feature regions, respectively.Finally, smoothedmodel is achieved through adjusting the mesh vertices according to the weighted average ofthe area and angle based on the normal vector adjusting. Experiment result of the dental modelshows that the method is effective and feasible.Based on the comparing and analyzing of the basic principle, characteristics, applications,merits and demerits of the typical blend surface construction methods, such as Rolling-ballblends, Partial Differential Equations, Energy method, this paper mainly studied theenergy-based method to construct blend surface based on quadrilateral regions and realizedthe blend surface construction between the crowns. Firstly, fast methods based on boundarycomparing and hash map are proposed on the basis of the tranditional method, and theextraction of the crown boundary is obtained. Secondly, on the basis of the crown boundaryextraction, this paper identified the quadrilateral regions as the blend area. Finally, thereasonable mathematical model is established under the constraints of boundary normal and boundary curvature.Through simplifying the mathematical model, the generalized Lagrangemultiplier method is adopted to absolve the model and obtained the control points, whichimplements the visualization of the blend surface between the crowns.This paper selected Visual Studio2005as the development tool. It realized the dentalmodel smoothing, the crown boundary extraction and blend surface construction between thecrowns. The results of the experiment show that the algorithms mentioned in this paper canachieve the desired effect, which has higher proficiency and better practicability.