Adobe After Effects Expressions and Scripting 2

Question 1

What does the `valueAtTime(t)` method do in an After Effects expression?

Accepted Answer

Returns the value of the property at a specified time `t` in seconds

Answer

valueAtTime(t) samples a property's value at any given time, enabling delay effects, echo trails, and time-offset animations.

Question 2

What does `effect("Slider Control")("Slider")` do in an After Effects expression?

Accepted Answer

References the value of a Slider Control effect applied to the current or target layer

Answer

This expression retrieves the current value of a Slider Control effect, letting you drive multiple properties from a single master slider.

Question 3

What does `Math.sin(time * frequency) * amplitude` create when applied to a Position expression?

Accepted Answer

A smooth sinusoidal oscillating motion at the given frequency and amplitude

Answer

Math.sin creates a smooth, predictable periodic oscillation — useful for pendulum swings, looping wave motion, or pulsing effects.

Question 4

What does the `index` expression variable return in After Effects?

Accepted Answer

The layer's order number (index) within the composition's layer stack

Answer

The `index` variable returns the layer's position in the layer stack (1-based), enabling offset animations that increment per layer.

Question 5

What does `toComp()` method do in After Effects expressions?

Accepted Answer

Converts a point from a layer's local coordinate space to the composition's coordinate space

Answer

toComp(point) transforms a 2D or 3D point from the layer's local space into the composition's global coordinate system.

Adobe After Effects Practice Test