Hi Giorgos,
Thanks a lot, I believe the whole team is happy to read your nice comments about the relaunch.
I wish you a nice 2012 as well.
The idea is (at least for me) to get things set up easily and keep the control as much as possible. Which is sometimes not possible of course (Control vs set up vs Effect, etc.)
I have attached a little set up. First we need to create a Cloth like object that is able to grow. Have an eye on the Spline “subdivision”, which means amount of points. I have used here a Water Shader, you might create a displacement movie, if your need is beyond that shader.
With this set up so far, we can control the growth and the movement of the surface.
Now we need to move it along a new Spline, which is typically done with a Spline Wrap. As the growth is already established, there is no need to animate things here. You might only set up the “keep length” or “fit spline” option.
Please have a look to the supplied file. The Spline that you might use in the Spline Wrap can be animated, e.g., scale wise, if you like to follow closely the great animation from Tim.
Alternative: Other methods comes to mind, e.g., with Point cache and with alpha maps (animated gradient) to change the length of the “cloth”. Cache is nice but take a little bit the initial interactivity away. You might explore this a little bit for your needs.
All the best
Sassi