CAD练习题18——利用固定角度三角形画不规则多边形

题目:

https://github.com/longlongpicture/myblogpicture/raw/master/p18-6.PNG

这道题不大好用平行四边形了,因为75度下边对应的两个角的度数目前都不知道,这就导致没法作目标直线的平行线。所以我们不妨换个思路。

1、先画已知部分。

https://github.com/longlongpicture/myblogpicture/raw/master/p18-1.PNG

2、连接两个端点,构成三角形,这时,我们发现上边要画的部分就是固定顶角三角形,这时就好下手了。

https://github.com/longlongpicture/myblogpicture/raw/master/p18-2.PNGhttps://github.com/longlongpicture/myblogpicture/raw/master/p18-3.PNGhttps://github.com/longlongpicture/myblogpicture/raw/master/p18-4.PNGhttps://github.com/longlongpicture/myblogpicture/raw/master/p18-5.PNG

3、清理图形。

https://github.com/longlongpicture/myblogpicture/raw/master/p18-6.PNG

CAD练习题17——利用平行四边形画不规则多边形5

题目:

https://github.com/longlongpicture/myblogpicture/raw/master/p17-6.PNG

这道题看上去不大容易直接构造平行四边形了,那又该用什么黑科技呢?

1、先画已知部分。

https://github.com/longlongpicture/myblogpicture/raw/master/p17-1.PNG

2、还是和之前 https://codinglonglong.github.io/posts/cadlian-xi-ti-13-li-yong-ping-xing-si-bian-xing-hua-bu-gui-ze-duo-bian-xing-1/ 相似的方法,构造一条和目标直线平行且相等的线。

https://github.com/longlongpicture/myblogpicture/raw/master/p17-2.PNG

3、问题是怎么把上一步的直线平移到两个圆上,并且还两端都各自正好搭到一个圆呢?下面看看黑科技。

https://github.com/longlongpicture/myblogpicture/raw/master/p17-3.PNGhttps://github.com/longlongpicture/myblogpicture/raw/master/p17-4.PNGhttps://github.com/longlongpicture/myblogpicture/raw/master/p17-5.PNG

4、清理图形。

https://github.com/longlongpicture/myblogpicture/raw/master/p17-6.PNG