Specifies how the world up vector used by the aim constraint is defined.
| SceneUp | Uses and defines the world up vector as the Unity Scene up vector (the Y axis). |
| ObjectUp | Uses and defines the world up vector as a vector from the constrained object, in the direction of the up object. |
| ObjectRotationUp | Uses and defines the world up vector as relative to the local space of the object. |
| Vector | Uses and defines the world up vector as a vector specified by the user. |
| None | Neither defines nor uses a world up vector. |