基于高光线法的曲面品质分析

【作者】 孙科峰；

【导师】 孙根正；

【作者基本信息】 西北工业大学 ， 机械设计及理论， 2005， 硕士

【摘要】 虚拟油泥建模(VCM,Virtual Clay Modeling)是一种基于体素的新型设计工具。其特点是可以适应创造性设计过程所提出的直观要求,因而在车身造型设计中得到了重视。虚拟油泥模型的可视化是通过渐进立方体(Marching Cubes)方法生成的表面三角网格实现的。在虚拟油泥建模中,虚拟曲面品质分析是不可缺少的重要环节。 高光线模型是一种可视化的曲面品质分析模型。本文首先在NURBS曲面上实现了连续曲面的高光线模型,然后将高光线模型拓展到三角网格曲面中。提出了三角网格曲面高光线模型的定义,讨论了相关性质及追踪方法,并在三角网格曲面上实现了高光线模型,验证了论文提出的相关理论。 本文还提出了一种新的基于矩形网格的等值线生成算法。该算法的优点是计算效率较高,避免了以往等值线追踪算法起始点选取困难、网格出口边判断复杂的问题。算法的追踪结果精度取决于等值点的计算方法,其精度是可控的。更多还原

【Abstract】 VCM (Virtual Clay Modeling) is a new type of modeling tool based on voxel model. It meets the need of intuition in the process of creative design. So, VCM is more attention-getting in the field of automobile design. VCM can be showed in the way of triangular mesh surface generated by Marching Cubes algorithm. Surface-quality assessment is indispensability in VCM.The highlight-line model is a visual tool in assessing the quality of a surface. Firstly, the highlight-line model on continuous surface is implemented. Then, the model is extended to triangular mesh surface. The definition of highlight-line model on triangular mesh surface is put forward. Its properties and tracing method are discussed. And the highlight-line model on triangular mesh surface is implemented. The theories put forward in this paper are demonstrated.A new contour line generating algorithm in rectangular meshes is put forward in this paper also. The algorithm is highly efficient. It avoids many problems that always encountered by traditional methods such as selection of beginning point, judgment of borderline. The precision lies on the computing method of contour points and can be controlled.更多还原