Slow Motion Effect in Unity

Altering the time pace in Unity is quite easy, all you need to do is change the value of Time.timeScale.

Time.timeScale is a value in Unity that controls time-dependent events, such as Update functions, animations, particles, physics, etc. When the timeScale is 1, time passes as fast as real-time, with 0.5 time passes 2 times slower than real-time, and with 2.0 the time passes twice as fast. Time.timeScale with the value of 0 pauses any framerate-dependent calculations, negative values are ignored.

However, just setting the value of timeScale is not enough to make a believable slow-motion effect.

Some components such as AudioSource are not affected by time, but luckily, changing their pitch is enough to add a slow-motion effect to the audio.

Slow motion in games refers to a visual and sometimes functional effect where the gameplay, graphics, and animations are slowed down to create a dramatic and stylized experience. It is used to emphasize key moments, improve player control, or add cinematic flair to gameplay sequences.

When the game is in slow motion, everything appears to move at a reduced speed compared to normal gameplay. This can include character movements, environmental interactions, and even projectile or particle effects. The effect is often achieved by adjusting the game's frame rate or by manipulating time-related variables in the game's code.

To make a slow-motion effect in the Unity game, we will need to write a script that will change the value of Time.timeScale and will change the pitch of all active Audio Sources.

Slow motion is the opposite of fast motion and is the process of slowing down the game speed.

• Create a new script, call it 'SC_SlowMotionEffect', remove everything from it then paste the code below inside it:

SC_SlowMotionEffect.cs

using UnityEngine;

public class SC_SlowMotionEffect : MonoBehaviour
{
    public float slowMotionTimeScale = 0.5f;
    public bool slowMotionEnabled = false;

    [System.Serializable]
    public class AudioSourceData
    {
        public AudioSource audioSource;
        public float defaultPitch;
    }

    AudioSourceData[] audioSources;

    // Start is called before the first frame update
    void Start()
    {
        //Find all AudioSources in the Scene and save their default pitch values
        AudioSource[] audios = FindObjectsOfType<AudioSource>();
        audioSources = new AudioSourceData[audios.Length];

        for (int i = 0; i < audios.Length; i++)
        {
            AudioSourceData tmpData = new AudioSourceData();
            tmpData.audioSource = audios[i];
            tmpData.defaultPitch = audios[i].pitch;
            audioSources[i] = tmpData;
        }

        SlowMotionEffect(slowMotionEnabled);
    }

    // Update is called once per frame
    void Update()
    {
        //Activate/Deactivate slow motion on key press
        if (Input.GetKeyDown(KeyCode.Q))
        {
            slowMotionEnabled = !slowMotionEnabled;
            SlowMotionEffect(slowMotionEnabled);
        }
    }

    void SlowMotionEffect(bool enabled)
    {
        Time.timeScale = enabled ? slowMotionTimeScale : 1;
        for (int i = 0; i < audioSources.Length; i++)
        {
            if (audioSources[i].audioSource)
            {
                audioSources[i].audioSource.pitch = audioSources[i].defaultPitch * Time.timeScale;
            }
        }
    }
}

• Attach the script above to any GameObject then press 'Q' in the game to activate/deactivate the slow-motion effect.

To make sure Rigidbodies are simulated smoothly during the slow-motion effect, set their Interpolate value to Interpolate or Extrapolate.