You will need to use Euler's angle if the pendulum is not a sphere,
for example:  when it is a cylinder, then, you can use the following rules to draw it:
1. rotate around z axis by \phi
2. rotate around y axis by -\theta
3. rotate around z axis by \phi

You can check out the following applet.

/htdocs/ntnujava/ejsuser/2/users/ntnu/fkh/pendulum3D3_pkg/pendulum3D3.propertiesFull screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License
Download EJS jar file(1549.7kB):double click downloaded file to run it. (5 times by 4 users) , Download EJS source (7 times by 4 users) View EJS source