Expression Help

[Mike Clasby]

Probably the easiest way is to make you number 1 in a text layer. We’ll parent it to a null, rotate the null to get a perfect circle.

Create a new Null layer. Move the null to where you want the center of rotation to be. Move the #1 layer next to the null, as far away as you want the radius to be. Now Parent the #1 layer to the null, Now rotate the null, say 10 revolution over 5 sec (use the numbers you need). Select the second rotation keyframe, right click, Keyframe Interpolation, Temporal Interpolation>Bezier. Now twirl down the rotation twirly (little triangle, and play with the rotation graphs until you get the acceleration you want.

Click the Motion blur for the #1 layer and for the comp, if there’s not enough blur, Ctrl K, to open the comp Settings Window, then click the Advanced Tab, and crank up the Shutter Angle to something like 720.

Tweak to taste.

[Filip Vandueren]

a simple expression for rotation could be:

slowFactor=2;
(time*time)/slowFactor;


this would have the rotation go faster and faster (exponentially). use the value of SlowFactor to finetune it.

As Mike suggested, apply this to a null and offset the 1 from the Null’s anchorpoint to have it rotate.
Give the number-Layer the same expression, but change the slowFactor to the negative amount of the null’s expr.: it will turn against the Null’s rotation and stay upright while following the path.

If you don’t need a perfectly circular path (depending on the shape of your O), animate your positions with the first keyframe at 0 and the last (equal to the first) at say two seconds.
Then give the Numbers position this expression:


lastKeyTime=2;
slowFactor=2;

t=(time*time)/slowFactor;
t=t%lastKeyTime;

valueAtTime(t);


this will loop your keyframes between time 0 and 2, and speed through them exponentially.

I have not tested this for typos.

[Mike Clasby]

Filip, Thanks for those expressions.