[Xinlai Ni]

I can understand only half of your question, but seems like you are looking for the
thisLayer.position.speed

property

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

I guess I didn’t understand how you want to specify the movement. Are you trying to manually move the slider around hoping to see your layers move their Z-coordinates accordingly? Are you going to control your slider by key-frames at the end? If all you need is a delay of the layer’s movement with respective the corresponding z-slider’s value, you can simply move valueAtTime as below (for each layer’s position property).

x = yourX;
y = yourY;
z = thisComp.layer("Control").effect("Slider")(1).valueAtTime(time - yourDelay);
[x, y, z]

This works only when your slider is animated somehow, e.g., via keyframing.

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

your expression was truncated, can you please paste again?
Thanks.

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

use this expression for the opacity:
selectedIndex = Math.floor(thisComp.layer(“Contorl”).effect(“Slider Control”)(1));
selectedIndex == index ? 100 : 0

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

This should be easy, for example you want to animate the rotation property with uniform angular acceleration ‘a’ until time ‘t’, after which it stays with the constant speed. Just apply this expression to your rotation property:

if (time < t) { 0.5 * time * time * a; } else { 0.5 * t * t * a + a * t * (time - t) }

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

I didn’t quite understand the relationship between the rotation of the cylinder to the falling of the object, can you explain more?
But for uniform acceleration from still, the formula is
displacement = acceleration * time * time / 2
you can apply that to either angular displacement or positional displacement.

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

It’s not natural to me to control how violent the camera shakes by controlling its wiggle frequency, I would use the wiggle amplitude for this purpose. Frequency is a subtle thing, it says for one second how many random wiggles are generated, so a frequency of 0.2 means one wiggle per 5 seconds, and it’s quite hard to have a definitive expectation out of this.

Anyway, have you tried to link the wiggle frequency with the camera’s ‘position.speed’ property? Something like
wiggle(freq, position.speed * 100)

Or at least, you can control the amplitude TOGETHER with the frequency to achieve what you want.

Hope this helps.

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

It’s as simple as linear scale:
Assuming your topmost text layer is at z=0 plane, and your camera is sitting at some negative z coordinate looking toward z+ direction (this is important!), apply this to the scale property of each text layer:
cameraZ = thisComp.layer(“Camera 1”).position[2];
s = 100 * (cameraZ – position[2]) / cameraZ;
[s, s, s]

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

The only thing is you are using the bitwise AND operator ‘&’ instead of logical AND operator ‘&&’, but in effect it should be the same given the way you use it.

Xinlai Ni
Software Engineer, Google Inc.

[Xinlai Ni]

It’s totally possible to simulate this using expressions:
The physics of rigid-body free-falling is pretty simple, you can get the formula from the high-school physics texts. It involves solving a quadratic equation. But the hard part is the collision detection, i.e. when the irregularly-shaped letter object bounces off the floor because the formula works for point-like objects. That makes it even more complex if you want the dropped object to rotate around its center of mass. It’s totally doable given some manual parameter-tweaking, and it’s guaranteed to be realistic because of the precision of the math.

Xinlai Ni
Software Engineer, Google Inc.