What is the main difference between Update() and FixedUpdate() methods?

The main difference between Update() and FixedUpdate() lies in their scheduling and purpose within Unity's game loop. Update() is called once per frame, which means that its execution frequency can vary depending on the frame rate of the game. This makes it ideal for tasks that need to be updated each frame, such as handling input or animating objects that do not rely on physics.

On the other hand, FixedUpdate() is called at consistent, fixed intervals regardless of the frame rate, making it the preferred method for physics calculations. This ensures that physics updates are smooth and predictable, as they are not influenced by frame rate fluctuations. By using FixedUpdate() for physics-related updates, you can achieve more consistent behavior in simulations, such as applying forces or managing Rigidbody physics interactions.

Understanding this distinction is crucial for optimizing game performance and ensuring that gameplay mechanics function correctly, especially in scenarios heavily reliant on physics. While Update() can be used for rendering and handling user inputs, FixedUpdate() should be the go-to for any operations associated with the physics engine.