I'm still working on the tutorial (should be able to post it in a day or two), but it isn't anything like as hard to do is it sounds. It's essentially a combination of methods you might use anyway. But patience is sometimes involved.

By the way, I'm not planning to explain how to make that particular animation in detail, just to use it as an example to explain the thinking behind the techniques. Also, I'll post it in a fresh thread rather than in this one.

Mike