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