Which collider type does the Unity physics system calculate the fastest?

The sphere collider is the fastest collider type for the Unity physics system due to its simple mathematical calculations for collision detection. Sphere colliders use a central point and a radius to define their shape, making it computationally efficient. This simplicity allows for rapid calculations when detecting intersections with other colliders, which is essential for maintaining high performance during physics simulations in a game.

Other collider types, such as box and capsule colliders, while still relatively fast, involve more complex calculations due to their geometric shapes. Mesh colliders, on the other hand, are the most complex, as they can represent arbitrary shapes and require significant processing power to compute collisions accurately. Consequently, the sphere collider provides an optimal balance of performance and functionality for many applications, particularly in scenarios where numerous collision checks are necessary.