What is keyframe animation in Unity?

Keyframe animation refers to a method of animation where specific frames, known as keyframes, are defined to represent different stages of an animation. Unity smoothly interpolates between these frames, creating the illusion of a change or movement.

Steps to create keyframe animation

Given below is a detailed guide on how to set up keyframe animation in Unity.

Select the GameObject

Create the GameObject of your choice.

Open animation window

Select the GameObject.
Go to Window > Animation > Animation.
- It opens up an animation window where you can create and set up new animations.

Create new animation

Click on Create button to create a new animation.
It prompts you to choose the name and location of the file.

Note: In the latest versions of Unity, creating a new animation creates an animator controller as well so, there is no need to set up animator controller separately.

Add properties

Select the properties of the GameObject that you are interested in modifying, such as position, scale, or color.

Enable animation recording

Click on the red circle named Enable/Disable Animation Recording button.
- It is used to define the keyframes for your animation.
- It allows you to record any changes you make to your GameObject.

Set keyframes

Drag the timeline cursor to the time where you want to change the properties of the GameObject.

You can directly modify the properties of the GameObject from the scene view.
Unity will automatically record this as a keyframe.

Disable animation recording

Click on the red circle again to disable the keyframe animation once you are done setting the keyframes.

Create a C# script

Create a new C# script to trigger the animations.

A sample C# script is given below.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class CubeController : MonoBehaviour
{
    public Animator animatorComponent;
    public const string WRAP_OUT = "WrapOut";
    public const string WRAP_IN = "WrapIn";
    // Start is called before the first frame update
    void Start()
    {
        animatorComponent = GetComponent<Animator>();
    }
    // Update is called once per frame
    void Update()
    {
        if (Input.GetKey(KeyCode.I))
        {
            animatorComponent.Play(WRAP_IN);
        }
        if (Input.GetKey(KeyCode.O))
        {
            animatorComponent.Play(WRAP_OUT);
        }
    }
}

Explanation

Lines 1–3: These lines make all the necessary imports.
Line 5: A class is declared named CubeController. It inherits methods from the class MonoBehaviour, a base class in Unity for scripts attached to the specific GameObjects.
Lines 7–9: These public variables are declared here. animatorComponent holds a reference to an Animator component, which is used for controlling animations. WRAP_OUT is a constant string with the value WrapOut: the name of the animation. WRAP_IN is another constant string with the value WrapIn: the name of the animation.
Lines 11–14: The Start() method is a Unity callback function that runs once when the GameObject is created. The animatorComponent variable is assigned the value of the Animator component attached to the same GameObject as the script.
Lines 17–27: The Update() method is another Unity callback function that runs once per frame. Here, the script checks for input from the user.
- If the I key is pressed (KeyCode.I), the Animator component's Play() method is called with the animation state WrapIn.
- If the O key is pressed (KeyCode.O), the Animator component's Play() method is called with the animation state named WrapOut.

Assign C# script to the GameObject

Drag and drop the C# from the project window onto the GameObject.

Play and test the animation

Save all the changes.
Click on Play to play the animation.
- You would be able to see the animated GameObject based on how you have set the keyfrmes.

Demonstration

Given below is a demonstration of an animated cube that is controlled by the WrapIn and WrapOut animations.

The WrapIn animation is used to wrap in the GameObject.
The WrapOut animation is used to wrap out the GameObject.