Reference Object Manager Tags Menu CINEMA 4D Tags Look At Camera Expression
Look At Camera Expression Basic TagTag Properties
If Change Pitch Rotation is enabled, the object’s Zaxis always points at the camera.
If the option is disabled, the pitch angle is not changed. Suppose you’re using a 2D tree in the scene (a plane with an alpha map). This tree must constantly face the camera, but also, its Pitch value must not change (i.e. it must remain perpendicular to the ground).
In such cases, disable Change Pitch Rotation and enable Camera Dependent (Basic Properties tab).