People often apply tracking data to which type of layer for parenting purposes?

Using a null object layer for parenting purposes is a common practice in Adobe After Effects, particularly when it comes to applying tracking data. A null object acts as an invisible layer that can control the transformations of other layers (such as position, rotation, and scale) when those layers are parented to it.

When you track motion in a scene, you can create a null object at the tracked position. This allows you to link other layers, such as video footage or images, to the null object. As a result, any movements captured in the tracking data will automatically influence the parented layers, creating a cohesive motion that follows the intended path. This technique is especially useful for complex scenes where you want multiple elements to move together in relation to a tracked anchor point without modifying each layer individually.

Text, shape, and solid layers can all be parented to a null object, but the null object itself is specifically designed for this type of function, making it the optimal choice for applying tracking data effectively.