类螺旋特征测点数据的闭曲面建模方法研究

复杂曲面及海量点云测量数据的曲面建模已成为通用CAD/CAM软件的重要功能;然而,对于复杂的闭曲面建模方法,仍然存在许多技术上的难题,至今尚未能很好的解决,比如,基于海量的测量数据,如何进行闭曲面特征点识别,如何进行区域分割与处理,这一切都使得闭曲面建模过程中很难采用已经成熟的自由曲面建模技术和方法.通过研究异步仿形测量原理以及测量数据类型,针对鞋楦测量形成的空间螺旋线数据特征,提出一种闭曲面建模方法.该方法包括如下步骤:首先对测量点数据处理;并以特征螺旋线数据为基础对曲面进行三角分割;最后,以三角Bezier曲面为基础进行曲面构造,并将各曲面进行拼接、裁剪,形成完整的曲面.采用该方法对鞋楦测量数据的建模实例说明,能够有效地对具有空间螺旋线数据特征的闭曲面进行数据处理、曲面重构,提高了产品建模效率.

Closed Surface Modeling with Helical Line Measurement Data

The surface modeling for free form surface and massive data points is becoming an important function in commercial CAD/CAM software.However,there are still many difficult problems to be handled in this area,especially for closed free form surface,such as the feature point acquisition from a massive data point,and how to section the massive data points as a valid surface patch,etc.In this paper,An effective method for cloud data closed surface modeling from asynchronous profile modeling measurement is presented.It includes three steps: first,the cloud data are preprocessed for smoothing;secondly,a helical line is segmented to form triangle meshes;at last,Bezier surface patches are created over triangle mesh and trimmed to shape an entire surface.In the end,a shoes last surface modeling illustrative example is given to show the availability of this method.