Unity Slow Motion

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 by 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.

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 inverse 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.