How to create a simple bobbing up and down motion expression?

[Peter J Kovacs]

Hi, I have a 3D object that I want to continuously bob up and down but I'm having trouble finding an expression to do this.

I would use wiggle on the Z except wiggle creates random motion and I need consistant up and down oscillations.

It seems simple but I can't figure it out... any ideas? Thanks.

-Pete

[Dan Ebberts]

You might try something like this for Size or Scale (make sure the freq variable matches your other exrpession):

amp = 20;
freq = 1;
s = amp*Math.sin(time*freq*Math.PI*2);
value*(1+s/100)

Dan

[lukep89382150]

Hey Dan,

Sorry in advance for bothering - I was wondering how I would go about adding a loop rule to this expression (i.e loop every 120 seconds).

Thank you!

[Pablo26312952bhpv]

Thank you, Dan! This is so simple yet effective.

[Manoel Flesch]

Hey guys, sorry to revive this but the expression is really great. I'm trying to use it for the z-axis and so far it worked the only thing I'm stuck with is how to create only positive values for the amplitude. Any idea on how to do this?

[ericsten]

Sorry for the late response.

One way to achieve this is by adding Math.abs() to your expression which will return the absolute values instead of true values (aka negative numbers get switched to positive).

Z=Math.abs(amp*Math.sin(time*freq*Math.PI*2));

- Eric

[sy4za]

Hi all,

The expression worked great. But i have no idea on if it is possible to decelerate the "bobbing/bopping" motion.

Do i need to adjust the value or frequency?

Thanks guys! x

[RAMQUE]

HOW CAN I STOP THIS?

[Rick Gerard]

Stop or start the effect by controlling amp and freq with sliders then animate the sliders.

[artichoked]

If you get an error, try adding curly brackets to the if/else statement:

if (t < StartTime) {value;} else {(value + [x,0,0])}