Animating a “head-bob”

[Kevin Camp]

so you just need the camera to bob up and down…

an expression like this for the camera’s position would effect just the y-pos and allow for further keyframing for the position:

f = 1 // bob frequency in times per second
a = 20 // bob amount in pixels
y = Math.sin(time*Math.PI*f)*a;
value-[0,y,0]

just modify the values for frequency and amount

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Matt Sepeta]

Thank you, this is perfect! I added this to the camera layers position than have a null as the camera parent to do the actual moving around.

Thanks again!!

Good Day
http://www.mattsepeta.com

[Matt Sepeta]

Sorry, one more quick question- How do I “hold” the expression? I am entirely new to using expressions. I tried putting a “toggle hold keyframe” at the point where I want the “bobbing” to pause for a bit, but it did nothing…

Good Day
http://www.mattsepeta.com

[Kevin Camp]

unfortunately that gets into a pretty tricky expression. i thought at first i could link the expression to the null’s speed, the idea being that if the null’s speed was zero, then it would stop bobbing, but the math is really not that simple…

what you could do is add a slider expression control to the null, then use the expression pickwhip to link the slider control value to the f variable in the expression. then you can keyframe that slider to match the timing of the position keyframes. a 0 value will stop the bobbing.

you might also inquire in the expressions forum to see if somebody who is better at expressions can create one that works with speed, or some other method to automatically stop and start the motion as the null moves.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW