【作者】 张春明；

【导师】 刘瑞祥； 陈立亮；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2005， 硕士

【摘要】 铸造凝固模拟技术已广泛地应用于生产实践中,它由前处理模块、计算模块和后处理模块组成。其中,后处理的任务通常是将数值数据可视化,构建出各种直观的三维图形,帮助用户理解数值模拟的结果。多年来,在Windows 环境下,传统的铸造CAE 软件可视化开发是基于Windows GDI 绘图方式的。在这种方式下,需要开发者将三维的实体信息转换为二维的平面图形信息,这个过程需要进行大量的矩阵变换操作,而且Windows GDI 设备绘图效率低下。因此,有必要寻找到一条方便、高效的绘图方式进行可视化开发。OpenGL 技术是国际上通用的三维图形软件标准,该标准是直接面向三维的,使用该技术在开发过程中可以免除许多复杂的坐标变换、消隐计算等操作,使开发者可以将更多的精力放在算法和数据结构的处理上。本文基于OpenGL 技术,在后处理模块中,对于表面网格单元的处理和数值鼠标的实现做了大量研究工作。在此过程中,重点研究了各类算法,包括实体表面搜索、轮廓线搜索、表面网格合并、轮廓线合并等算法,并根据这些算法建立了一系列的数据结构。这些算法和数据结构都围绕着一个问题,就是如何减少三维实体的点阵信息,以提高三维图形的显示速度。最后用程序实现了多种类型数值画面的的旋转、缩放、剖切等,并利用反求定位和显示刷新实现了OpenGL 下的数值鼠标技术。在三维坐标可视化精确定位技术方面,针对STL 文件的剖分及装配问题,实现了单个STL 文件的实时动态显示,提出了计算截面轮廓线和三维坐标可视化精确定位的算法,并用程序实现了显示剖分截面以及通过鼠标精确定位三维坐标的方法。为了方便用户进一步对已获取的坐标值进行修正,用户还可以对这些坐标值进行编辑、删除、插入等操作。更多还原

【Abstract】 The technology of Solidification Simulation of Casting has been widely used in production and it is composed of the pre-processor, calculation and post-processor. The function of the post-process in solidification simulation is visualization of the data of calculation, with multiple kinds of pictures to help users to understand the simulation results. For many years, under the platform of MS Windows, the traditional development method of visualization of CAE software is based on GDI graph method. In this method, the developers should transform the 3D entity information to 2D graph, in which much matrix transform work should be done. However, the drawing efficiency of Windows GDI is very low. So it is necessary to find a new convenient and efficient way to develop visualization. The OpenGL is now an universal 3D technology directly and the developers who use this technology may not concern about many complicated coordinate translation and 3D shadow calculating, so they can pay more attention to the processing of algorithm and data structure. In the post-processor of “HuaZhu CAE”software the management of surface element of grid and the numerical mouse based on OpenGL are investigated in this paper. In this module, algorithms are focused on the including searching surface, searching contour line, combining of surface element as well as combining of contour line, and then a series of data structure is built. The algorithms and the data structure are employed for reducing the grid information of 3D entity, so as to improve the display velocity of the 3D entity. At last, the rotating, zoom in and zoom out, cutaway and so on of several kinds of numerical pictures are developed, and numerical mouse based on OpenGL is developed helped by reversing 3D position and refreshing display. On the study of the visualizing 3D accurate locating technology, aimed at cutaway view of STL entities and the assembly of them, single STL entity can be rotated and zoomed in real-time, and the algorithms of section contour line making and the visualizing 3D accurate locating technology were put forward and developed. To be convenient for users to modify the 3D coordinates they have got, they can operate on these 3D coordinates, such as editing, deleting, inserting and so on.更多还原