A null object is the layer you reach for when several layers need to move as one. This article covers how After Effects creates nulls and parents layers natively, and how Motion Studio's Null tool does both in one click with the anchor point already centered.
Setting up a null and parenting natively
A null is an invisible layer with a full set of transform properties and no render output. It exists to be a parent: move, rotate, or scale the null and every layer parented to it follows.
Create one with Layer > New > Null Object (Cmd+Opt+Shift+Y on Mac, Ctrl+Alt+Shift+Y on Windows). The null appears at the center of the composition as a 100 by 100 pixel outline. Its anchor point sits at the top-left corner of that square rather than the center, so rotating or scaling through the null pivots around the corner until you fix it.
Parenting lives in the Parent & Link column of the Timeline panel. Drag the pickwhip from the child layer onto the null, or pick the null from the column's dropdown. With several layers selected, one pickwhip drag parents all of them. Hold Shift while parenting and the child snaps to the parent's position, rotation, and scale instead of staying put.
Recent versions add null generators for specific cases. Window > Create Nulls From Paths.jsx makes a null for each vertex of a path, and Animation > Keyframe Assistant > Null Controllers for Positional Points creates a controller null for a position property.
None of this is difficult, but it is four steps every time: create the null, center its anchor point, move it to where the group sits, then parent. A project with a dozen rigs can be a tedious number of clicks.
How do I create a null and parent layers to it in one click?
Select the layers and run Null in Motion Studio. The tool adds a null with a centered anchor point and parents every selected layer to it. With nothing selected, Null adds a plain null with a centered anchor point, ready to use.
The parented layers stay exactly where they are; only the hierarchy changes. Rotate or scale the null afterwards and the group pivots around the null's own center instead of a corner, without needing to use the Pan Behind tool.
How do I chain layers together instead of grouping them?
Motion Studio's Parent tool chains a selection. Select the layers in the order you want them linked and run Parent, and each layer is parented to the one before it. That gives you a tail, rope, or hinge rig without pickwhipping each link by hand.
What about puppet pins?
Pin+ converts puppet pins on a selected layer into null controllers, so a character rig gets the same null-based control as a shape rig.
Full feature documentation: Null Guide.
Common Questions about Null Objects in After Effects
What is a null object in After Effects?
A null is a layer with transform properties and no visible content. It never renders. Its only job is to control other layers through parenting, expressions, or camera and light targeting.
How do I center the anchor point of a null?
Natively, select the null and double-click the Pan Behind tool, or press Cmd+Opt+Home on Mac, Ctrl+Alt+Home on Windows. Motion Studio's Null tool creates the null with the anchor point already centered.
How do I parent multiple layers to one null at once?
Natively, select all the child layers and drag the pickwhip from any one of them onto the null; every selected layer takes the parent. In Motion Studio, select the layers and run Null, which creates the null and parents the selection in the same step.
Does parenting move my layer?
No. Parenting records the relationship at the moment you set it and the child stays in place. It only moves if you hold Shift while parenting, which snaps the child to the parent's transform.
How do I unparent a layer without it jumping?
Set the Parent & Link column back to None. After Effects adjusts the layer's transform values so it keeps its current position, scale, and rotation on screen.
Do null objects render?
No. Nulls are excluded from render output, so there is no need to hide or shy them before rendering, though shying them keeps a long timeline readable.
Can I create a null from a puppet pin?
Not natively. Motion Studio's Pin+ turns each puppet pin on the selected layer into a null controller.
Null is available now as part of Motion Studio. Try Motion Studio free for 7 days, no credit card required.