The Time.timeScale property defines the rate at which time passes in your game world relative to real time. A Time.timeScale value of 1.0 means your in-game time matches real time. A value of 2.0 makes time pass twice as quickly in your game as in the real world, which speeds up the action in your game. A value of 0.5 slows gameplay down to half speed. A value of zero makes your in-game time stop completely.
Time.timeScale doesn’t actually slow execution but instead changes the time step reported to the Update and FixedUpdate functions with Time.deltaTime and Time.fixedDeltaTime.
Your Update function may be called just as often when you reduce the time scale, but the value of Time.deltaTime each frame will be less. Other script functions aren’t affected by the time scale, so you can for example display a GUI with normal interaction when the game is paused.
For special time effects such as slow-motion, it’s sometimes useful to slow the passage of game time so that animations and time-based calculations in your code happen at a slower pace. Furthermore, you may sometimes want to freeze game time completely, as when the game is paused.
The Time window has a property to let you set the time scale globally but it’s usually more useful to set the value from a script using the Time-timeScale property:
//C# script example
using UnityEngine;
using System.Collections;
public class ExampleScript : MonoBehaviour {
void Pause() {
Time.timeScale = 0;
}
void Resume() {
Time.timeScale = 1;
}
}