基于参数曲面建模的车身表面逆向设计研究

Study on Autobody Surface Reversing Design Based on Parametric Modeling

针对在汽车车身设计逆向工程过程中,由于雕塑模型的精度有限以及三坐标测量的机测误差,所得的散乱点不能真实反映曲面形状而建立了一种曲面拟合方法,能够减小误差较大点的影响,保证据散乱点求得的曲面最接近于理想"曲面.并简述了车身曲面逆向设计拟合方法的数学模型和CATIA软件创成式曲面设计模块的主要功能.将车身曲面的逆向设计分为2D图纸和3D实物逆向设计2类,给出设计流程和应用开发实例,解决了设计中容易出现的问题.

In reversing engineering for autobody design, within the point cloud or measured data there must be some points that cannot be used for a real surface design because of the limited shape precision of a sculptured model and the measuring error. So a surface fitting method is presented to decrease the effect of large - error wild points and ensure the designed surface most equal to the ＂real＂ surface. The mathematic model for freeform surface reversing design and the main modeling functions of the generative surface design in CATIA are briefly presented. The reversing design method for autobody surfaces is divided into two types, generated individually from 2D drawings and 3D white autobody. The design process flow chart is expressed, and some development examples are given, meanwhile, the problems commonly happened in body design are discussed and solved.