Rapid shaking sprite on z-axis rotation

Hey Airsoft! 

I suspect you are using Degrees when trying to set the rotation. Lens Studio however expects Radians when scripting rotation. Here's a simple example of converting degrees to Radians:

 var DEG_TO_RAD = 0.0174533;
 script.Mesh1.getTransform().setLocalRotation( quat.quatFromEuler( 90.0 * DEG_TO_RAD, 45.0 * DEG_TO_RAD, 0.0 * DEG_TO_RAD) );

Finally, I created a simple script a while back that continuously spins an object. I modified it here a bit using a Math.sin to spin it back and forth. Add the script and make sure to select the Frame Updated event in the event dropdown. Then, set the spinObject to your billboard. Finally tune the spinSpeed and the spinDegrees vars in your Inspector panel. 

// -----JS CODE-----
// @input SceneObject spinObject
// @input float spinSpeed = 4.0
// @input float spinDegrees = 45.0

var DEG_TO_RAD = 0.0174533;
var spinTransform = script.spinObject.getTransform();
var spinVal = Math.sin( getTime() * script.spinSpeed ) * ( script.spinDegrees * DEG_TO_RAD );

spinTransform.setLocalRotation( quat.quatFromEuler( 0.0, 0.0, spinVal ) );