天天课堂 发表于 2009-8-12 16:24:00

使用对象捕捉精确画线

<p></p><p><table cellspacing="0" cellpadding="0"><tbody><tr><td class="t_msgfont" id="postmessage_407">打开文件“1-3.dwg”，使用LINE命令并结合对象捕捉将图1-5中的左图修改为右图。这个练习的目的是使读者掌握“交点”、“切点”、“延伸点”等常用对象捕捉的方法。<br/><img width="345" height="209" alt="" src="http://www.ttketang.com/home/attachment/200908/12/113_1250039975OPll.jpg" complete="complete"/><br/>1-5利用对象捕捉画线<br/>操作范例——用LINE命令并结合对象捕捉精确画线<br/>1.&nbsp; &nbsp; &nbsp; &nbsp; 画线段BC、EF等，B、E两点的位置用正交偏移捕捉确定，如图1-6所示。<br/>命令: _line 指定第一点: from&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //使用正交偏移捕捉<br/>基点: end于 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉偏移基点A<br/>&lt;偏移&gt;: @6,-6&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //输入B点的相对坐标<br/>指定下一点或 [放弃(U)]: tan到&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉切点C<br/>指定下一点或 [放弃(U)]:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //按Enter键结束<br/>命令:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //重复命令<br/>LINE 指定第一点: from&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //使用正交偏移捕捉<br/>基点: end于&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉偏移基点D<br/>&lt;偏移&gt;: @6,6&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //输入E点的相对坐标<br/>指定下一点或 [放弃(U)]: tan到&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉切点F<br/>指定下一点或 [放弃(U)]:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //按Enter键结束<br/>命令:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //重复命令<br/>LINE 指定第一点: end于&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉端点B<br/>指定下一点或 [放弃(U)]: end于&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉端点E<br/>指定下一点或 [放弃(U)]:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //按Enter键结束<br/>结果如图1-6所示。<br/>知识难点：正交偏移捕捉可以使用户相对于一个已知点定位另一点。操作方法是：用户先捕捉一个基准点，然后输入新点相对于基准点的坐标（相对直角坐标或相对极坐标），这样就可从新点开始作图了。<br/><img width="192" height="196" alt="" src="http://www.ttketang.com/home/attachment/200908/12/113_12500596958lQ8.jpg" complete="complete"/><br/>1-6画线段BC、EF等<br/>2.&nbsp; &nbsp; &nbsp; &nbsp; 画线段GH、IJ等，如图1-7所示。<br/>命令: _line 指定第一点: int于&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉交点G<br/>指定下一点或 [放弃(U)]: per到&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉垂足H<br/>指定下一点或 [放弃(U)]:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //按Enter键结束<br/>命令:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //重复命令<br/>LINE 指定第一点: qua于&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉象限点I<br/>指定下一点或 [放弃(U)]: per到&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉垂足J<br/>指定下一点或 [放弃(U)]:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //按Enter键结束<br/>命令:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //重复命令<br/>LINE 指定第一点: qua于&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉象限点K<br/>指定下一点或 [放弃(U)]: per到&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉垂足L<br/>指定下一点或 [放弃(U)]:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //按Enter键结束<br/>结果如图1-7所示。<br/><img width="199" height="210" alt="" src="http://www.ttketang.com/home/attachment/200908/12/113_12500596962uDs.jpg" complete="complete"/><br/>1-7画线段GH、IJ等<br/>3.&nbsp; &nbsp; &nbsp; &nbsp; 画线段NO、OP等，如图1-8所示。<br/>命令: _line 指定第一点: ext&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉延伸点<br/>于 19&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //输入N点与M点的距离<br/>指定下一点或 [放弃(U)]: par&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //利用平行捕捉画平行线<br/>到&nbsp;&nbsp;4&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //输入O点与N点的距离<br/>指定下一点或 [放弃(U)]: par&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //使用平行捕捉<br/>到 8&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //输入P点与O点的距离<br/>指定下一点或 [闭合(C)/放弃(U)]: par&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //使用平行捕捉<br/>到 13&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //输入Q点与P点的距离<br/>指定下一点或 [闭合(C)/放弃(U)]: par&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //使用平行捕捉<br/>到 8&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //输入R点与Q点的距离<br/>指定下一点或 [闭合(C)/放弃(U)]: per到&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //捕捉垂足S<br/>指定下一点或 [闭合(C)/放弃(U)]:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //按Enter键结束<br/>结果如图1-8所示。<br/>知识难点：延伸点捕捉使用户可以从线段端点开始沿线的方向确定新点。操作方法是：先把光标从线段端点开始移动，此时系统沿线段方向显示出捕捉辅助线及捕捉点的相对极坐标，再输入捕捉距离，AutoCAD就定位一个新点。<br/><img width="192" height="233" alt="" src="http://www.ttketang.com/home/attachment/200908/12/113_1250059697dM93.jpg" complete="complete"/><br/>本文转载于<a href="http://www.ttketang.com/">http://www.ttketang.com/</a>，我从那上面学到了很多有用的东西，感兴趣的也去看一下，绝对会有收获的</td></tr></tbody></table></p>
页: [1]
查看完整版本: 使用对象捕捉精确画线