基于非均匀有理B样条的多尺度三维建模研究

Research on 3D Modeling of Multi-scale based on Non-uniform Rational B-spline

机械加工零件时,由于加工误差的存在导致模型表面不够光滑。传统计算机辅助设计方法在构建机械零件模型时,无法对零件表面进行表达,因此提出一种随机生成点的算法来模拟零件表面因粗糙度导致波峰、波谷的出现。为了保证生成的点在零件粗糙度范围内,将某一范围作为约束得到所需要点的坐标,然后将点插入利用非均匀有理B样条表达的模型,使建模能够更接近真实零件。最终得到的模型实现了宏观尺度上模型结构的表达和微观尺度上模型表面质量的表达。该算法实现点的随机生成,生成数据有60%符合要求,可用于体参数化建模,实现模型宏观结构与微观波峰、波谷的表达。

When machining parts, model surface is not smooth enough due to processing errors. Traditional computeraided design method cannot express part surface when constructing the mechanical part model. Therefore, this paper proposes an algorithm of randomly generating points to simulate the appearance of the peaks and valleys caused by the roughness of part surface. In order to ensure that the generated points are within the roughness range of the part, a certain range is used as a constraint to obtain the coordinates of the required points, and then the points are inserted into the model expressed by non-uniform rational B-spline so that the modeling can be closer to the real part. The final model can realize the expression of the model structure on the macroscale and the expression of the surface quality of the model on the microscale.The algorithm realizes random generation of points, and 60% of the generated data meets the requirements and can be used for volume parametric modeling, realizing the expression of peaks and valleys of the model on both the macroscopic and microscopic structure.