Solution 1 : Posted by Ken Broomfield on AE List Oct 27 2002)
minTracking = 0;
maxTracking = 100;
maxSize = effect("Basic Text").param("Size").value_at_time(0);
minSize = effect("Basic Text").param("Size").value_at_time(10000);
(maxSize - effect("Basic Text").param("Size")) / (maxSize - minSize) *
(maxTracking - minTracking) + minTracking
You need to plug in the desired maximum and minimum values you want for the
Tracking parameter in the minTracking and maxTracking assignments at the
top. I've also assumed that the maximum text size is at or after time
0:00:00, and minimum text size is at or before 10,000 seconds into the comp.
I'm also using Basic Text here -- you'd need to change some names for Path
The essence of this is pretty simple -- I'm no math genius, so anyone should
be able to figure it out.
Solution 2 : (Posted by Dan Ebberts on Oct 27 2002)
"k" is the font size where you want the tracking to be zero. "factor"
determines how fast the tracking increases as font size decreases.