What must be defined in an Animator Controller to control character animations effectively?

To control character animations effectively in Unity, it is essential to define animation states and transitions in an Animator Controller. The Animator Controller acts as a state machine that manages different animations for a character, allowing you to switch between various animation clips based on defined triggers or conditions.

Animation states represent the different animations that can be played, such as walking, running, and jumping. Transitions dictate how and when to move from one state to another, enabling smooth animation flows. For instance, a character might transition from a 'Walking' state to a 'Jumping' state when a jump command is issued.

This structured approach to defining states and transitions is what allows for dynamic and responsive character animations, enhancing the overall gameplay experience. Without properly defined states and transitions, animations would not execute in a coherent or realistic manner, making it crucial for effective character animation control in Unity.