How to Wiggle Position Without Affecting Z in After Effects

Applying the wiggle expression to a 3D layer in Adobe After Effects usually shifts the layer across the X, Y, and Z axes simultaneously, causing unintended depth movement. This guide explains how to isolate the wiggle effect exclusively to the X and Y dimensions while keeping the Z-axis locked in place, using both a straightforward expression method and the Separate Dimensions technique.

The Expression Method

By default, applying wiggle(frequency, amplitude) to a 3D layer outputs a three-dimensional array [x, y, z]. To prevent the layer from moving forward or backward in 3D space, you must capture the wiggle values for X and Y while passing the layer’s original, un-wiggled value to Z.

  1. Select your 3D layer in the timeline and press P to reveal the Position property.
  2. Hold Alt (Windows) or Option (macOS) and click the stopwatch icon next to Position to open the expression editor.
  3. Paste the following expression:
w = wiggle(3, 50);
[w[0], w[1], value[2]];
  1. Click outside the text box to apply the expression.

How It Works

  • w = wiggle(3, 50); calculates a wiggle occurring 3 times per second with a range of 50 pixels.
  • w[0] extracts only the calculated X-axis wiggle.
  • w[1] extracts only the calculated Y-axis wiggle.
  • value[2] references the layer’s native Z-axis position value, leaving its depth completely unaffected by the wiggle.

The Separate Dimensions Method

If you prefer not to write an array-based expression, you can separate the spatial dimensions directly within After Effects:

  1. Select your 3D layer and press P to reveal Position.

  2. Right-click on the word Position and choose Separate Dimensions.

  3. The property will split into X Position, Y Position, and Z Position.

  4. Hold Alt / Option and click the stopwatch on X Position, then enter:

    wiggle(3, 50);

  5. Repeat the process for Y Position.

  6. Leave Z Position empty to maintain your original depth position without movement.