Spiral Movement
Posted: Thu Dec 01, 2011 4:04 am
How do I start with a small line and make it grow into a continuing spiral? 
draw the spiral path (you can use the draw shape tool - the button on the far right will create a spiral) - then you can use the stroke exposure to make it draw in or out - click and drag on the shape to shorten the line to a 'hidden' starting point. You can also alt+click to start at the other end.
By animating both ends, you could have a short line that follows the entire spiral - if you keep their distance the same from eachother it will look like a single short line.