Hi,

I'm assuming that by "computer animated design" you mean create a 3d model that can be printed. Is that what you mean?

If so here are some steps that I take:

1. Identify the need and think about how to solve it.
2. Do some sketches that represent ideas and concepts that could be made to solve the problem.
3. Go over your ideas and weed out the weaker ones, modify the stronger ones and come up with your initial prototype design.

Here's where it get's a little more involved.

4. You'll need a 3d program to build your part or parts. Part of the issue is that you'll have to learn to drive the software before you can build anything. Some programs are easier to learn and use than others but the theory is fundamentally the same. There are some free programs out there that you can find with Google searches. Here's a handy link: http://reprap.org/wiki/Useful_Softwa...D_CAD_software
5. Model your parts and then print your parts and test them.
6. If necessary, modify the models of your parts to make them better or to make them work as intended and reprint.
7. Test and modify again if necessary.
8. Once satisfied, save the GCode and .stl files and then print as often as you like.

What's cool is that the whole process is not that complicated. Once you get a printer and get it printing well then that part is done. Then you learn enough to make models in your 3d software. So, that step is done. Lastly, the only limitation is your imagination.

If this don't answer your question properly let me know...have fun...