Non-uniform rational B-spline (NURBS) curves and surfaces are very important tools for model- ling curves and surfaces. Several important details, such as the choice of the sample points, of the parame- terization, an...Non-uniform rational B-spline (NURBS) curves and surfaces are very important tools for model- ling curves and surfaces. Several important details, such as the choice of the sample points, of the parame- terization, and of the termination condition, are however not well described. These details have a great in- fluence on the performance of the approximation algorithm, both in terms of quality as well as time and space usage. This paper described how to sample points, examining two standard parameterizations: equi- distant and chordal. A new and local parameterization, namely an adaptive equidistant model, was pro- posed, which enhances the equidistant model. Localization can also be used to enhance the chordal parameterization. For NURBS surfaces, one must choose which direction will be approximated first and must pay special attention to surfaces of degree 1 which have to be handled as a special case.展开更多
讨论了汽车制动性能分析系统(system for analysis of automobile braking performance,ABPAS)的设计过程,系统采用面向对象的程序设计方法,运用当今流行的软件模块化设计思想组织数据结构,对每个计算模块采用类的形式来实现,每次运行...讨论了汽车制动性能分析系统(system for analysis of automobile braking performance,ABPAS)的设计过程,系统采用面向对象的程序设计方法,运用当今流行的软件模块化设计思想组织数据结构,对每个计算模块采用类的形式来实现,每次运行都是该类的一个实例的计算,类与类之间互相独立,使得系统对数据的计算和存储都十分方便,充分体现了面向对象方法的基本特征。展开更多
基金Supported by the Company ProCAEss GmbH, Landau in der Pfalz, Germany
文摘Non-uniform rational B-spline (NURBS) curves and surfaces are very important tools for model- ling curves and surfaces. Several important details, such as the choice of the sample points, of the parame- terization, and of the termination condition, are however not well described. These details have a great in- fluence on the performance of the approximation algorithm, both in terms of quality as well as time and space usage. This paper described how to sample points, examining two standard parameterizations: equi- distant and chordal. A new and local parameterization, namely an adaptive equidistant model, was pro- posed, which enhances the equidistant model. Localization can also be used to enhance the chordal parameterization. For NURBS surfaces, one must choose which direction will be approximated first and must pay special attention to surfaces of degree 1 which have to be handled as a special case.
文摘讨论了汽车制动性能分析系统(system for analysis of automobile braking performance,ABPAS)的设计过程,系统采用面向对象的程序设计方法,运用当今流行的软件模块化设计思想组织数据结构,对每个计算模块采用类的形式来实现,每次运行都是该类的一个实例的计算,类与类之间互相独立,使得系统对数据的计算和存储都十分方便,充分体现了面向对象方法的基本特征。
