【作者】 夏丽丽；

【导师】 刘新；

【作者基本信息】 华中科技大学 ， 机械设计及理论， 2004， 硕士

【摘要】 网络远程教育是当前发展最快的领域之一,它集计算机辅助教学CAI、现代多媒体技术和网络技术于一体,实现教育资源共享,使传统的教学模式焕发生机。本文在对几种典型的交互技术进行了比较,并且对《机械制图》远程教学特点进行分析的基础上,确定采用ActiveX技术开发一个网络在线绘图工具。使学生可以在客户端进行交互式绘图,并且通过组件接口将学习信息反馈到教学管理系统,使教师可以掌握学生的学习情况。为《机械制图》远程教学提供了一个教学平台。针对《机械制图》课程的教学特点和工程图样的绘制要求,对在线绘图工具进行了完善和扩充:完善了二维图形的绘制、编辑等功能;添加了三视图智能导航功能,设计了基于特征的图元数据结构。同时通过对学生图形作业的预处理,避免了在进行几何图形形状完整性判别时,由于绘图方式不同而可能出现的误判,进一步完善了《机械制图》作业的自动批改功能。通过对工程图样尺寸标注特点的分析,并结合二叉树数据结构的特点,提出了利用尺寸的封闭性来进行尺寸标注完整性判别的方法。通过对图元数据结构的遍历,生成三个方向上的尺寸二叉树;然后利用基于特征的图元结点数据,实现尺寸标注的自动批改。最后,对全文进行总结,并指出了本课题进一步研究的方向、工作要点和适宜采用的技术方法。更多还原

【Abstract】 Net-based distance education is one of the fastest developing fields at present, which integrates CAI, modern multimedia technology and Internet technology, makes educational resource shared by all the people, and brings vitality to traditional education with the advantages of network and multimedia technology.By analyzing several typical interactive techniques and the characteristics of long-distance teaching of mechanical drawing, the paper develops an on-line drawing system with ActiveX, which realizes that students make drawings interactively on client PC, and sends the feedbacks of learning to the teaching management system through the interface of ActiveX. It provides a platform for mechanical drawing teaching.In allusion to the characteristics of mechanical drawing and the requirements of engineering drawing, the paper improves and extends the on-line drawing tool: consummating the functions of drawing and editing, adding the function of navigation for three principal views, designing a feature-based data structure. At the same time, through the pretreatment of the students’ homework, the mistakes induced by using different ways of drawing when the integrity of geometric drawing is distinguished, are removed. This further improves the automatic correcting of mechanical drawing homework.After analyzing the characteristics of dimensioning and the data structure of Binary Tree, a method is put forward to judge the integrality of dimensioning by using the closing of dimensions. By traversal of the datum of drawings, the binary trees of dimensions are built in three directions. Then using the feature-based knot datum of drawing, the automatic correction of dimensioning can be realized.In the end, give a summarization, and point out the direction, main work and proper method for further research on this task.更多还原