Use python matplotlib to create 3D vector-based graphics, 3D vector graphics DIY

I drew the following graphs using Python and it's Matplotlib. If you are interested in the python code, they are here (not including the first gyroscope figure, will be added later). I am trying to improve the code into many functions/modules so that drawing can be convenient and automated. The part related to plotting starts from line 128, because this is just a portion of another bigger project. Just want to show this is not as time-consuming as one may think it is. We can create or draw beautiful vector-based graphs without buying expensive software like Adobe Illustrator or Acdsee Canvas. However as you can guess with this method you will need the numerical x,y,z locations of everything! (which is generated from yet another portion of the program!)

direction of friction force of rolling objects 有外力作用的的純滾動摩擦的作用力方向討論

這是一題常見於研究所考試試題的延伸討論。

試題舉例：國立成功大學96學年度碩士班招生考試試題，編號224，系所:醫學工程研究所甲組，科目：工程力學

這邊詳細的討論幾種較難的延伸型態，並審視磨擦力作用於滾動物體的方向，因摩擦力的方向很容易弄錯。有趣的是這些型態在日常生活中都很常見。

A sectional material I wrote up for university physics. These are more advanced problems for 1st and 2nd year engineering in university.

重新將我的手稿排版(latex): 排版完成2016/6/18

Direction of Friction in rolling motion (without slipping)

我的部落格內的相關文章：
http://whymranderson.blogspot.tw/2013/06/3-dimentional-rolling-coin-simulation.html
http://whymranderson.blogspot.tw/2013/02/two-coins-roll-without-slipping-puzzle.html

舊手稿

direction of Rolling Friction