Animation events in Unity - Step-by-Step Execution

Concept Flow - Animation events

Start Animation

↓

Animation Playing

↓

Animation Event Triggered?

No→Continue Animation

Yes↓

Call Specified Function

↓

Continue Animation

↓

Animation Ends

Animation plays and checks for events at specific frames; when an event triggers, it calls a function, then continues.

Execution Sample

Unity

void Footstep() {
    Debug.Log("Footstep sound plays");
}

// Animation event calls Footstep() at frame 10

Defines a function Footstep() called by an animation event during playback.

Execution Table

Step	Animation Frame	Event Triggered?	Action	Output
1	1	No	Play animation frame 1	No output
2	5	No	Play animation frame 5	No output
3	10	Yes	Call Footstep()	Logs: Footstep sound plays
4	15	No	Play animation frame 15	No output
5	End	No	Animation ends	Animation stops

💡 Animation reaches end frame, no more events to trigger

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
Animation Frame	0	1	5	10	15	End
Event Triggered	False	False	False	True	False	False
Output Log	""	""	""	"Footstep sound plays"	"Footstep sound plays"	"Footstep sound plays"

Key Moments - 3 Insights

Why does the function Footstep() only run at frame 10?

Because the animation event is set to trigger only at frame 10, as shown in execution_table row 3.

Does the animation stop when the event triggers?

No, the animation continues playing after the event calls the function, as seen in steps 4 and 5.

What happens if no event is set on a frame?

The animation just plays that frame without calling any function, as shown in steps 1, 2, and 4.

Visual Quiz - 3 Questions

Look at the execution table, what is the animation frame when the event triggers?

A 15

B 5

C 10

D 1

💡 Hint

Check the 'Animation Frame' and 'Event Triggered?' columns in execution_table row 3

At which step does the output log show 'Footstep sound plays'?

A Step 3

B Step 2

C Step 4

D Step 1

💡 Hint

Look at the 'Output' column in execution_table row 3

If the event was moved to frame 5, what would change in the execution table?

A Output log would show 'Footstep sound plays' at frame 15

B Event Triggered would be Yes at frame 5 instead of 10

C Animation would stop at frame 5

D No changes would happen

💡 Hint

Refer to how event triggers are marked in the 'Event Triggered?' column

Concept Snapshot

Animation events let you call functions at specific frames during animation playback.
Set events in the animation editor to trigger functions.
When the animation reaches that frame, it calls the function.
Animation continues playing after the event.
Useful for syncing sounds or effects with animation.

Full Transcript

Animation events in Unity allow you to run code at exact frames during an animation. The animation plays frame by frame. When it reaches a frame with an event, it calls the linked function, like Footstep() in the example. The animation does not stop; it keeps playing after the event. This helps add sounds or effects timed perfectly with the animation.

Practice

1. What is the main purpose of animation events in Unity?

easy

A. To run code at specific times during an animation

B. To change the animation speed dynamically

C. To create new animations automatically

D. To export animations to other software

Solution

1. Step 1: Understand animation events

   Animation events allow you to trigger code at exact moments in an animation timeline.

2. Step 2: Compare options

   Only To run code at specific times during an animation describes running code at specific times, which matches the purpose of animation events.

3. Final Answer:

   To run code at specific times during an animation -> Option A

4. Quick Check:

   Animation events = run code at specific times [OK]

Hint: Animation events trigger code during animation playback [OK]

Common Mistakes:

• Confusing animation events with animation speed control
• Thinking animation events create animations
• Assuming animation events export animations

2. Which of the following is the correct way to declare a method that can be called by an animation event in Unity?

easy

A. public string PlaySound(int volume, string soundName)

B. private int PlaySound(string soundName)

C. public void PlaySound()

D. void PlaySound(float speed, int count)

Solution

1. Step 1: Recall animation event method rules

   Methods called by animation events must be public and have zero or one parameter.

2. Step 2: Analyze options

   public void PlaySound() is public with zero parameters, valid for animation events. Others have wrong access or multiple parameters.

3. Final Answer:

   public void PlaySound() -> Option C

4. Quick Check:

   Animation event methods = public + 0 or 1 parameter [OK]

Hint: Animation event methods are public with max one parameter [OK]

Common Mistakes:

• Using private methods for animation events
• Adding multiple parameters to the method
• Returning a value from the method

3. Given this code snippet attached to an animation event:

public void PrintMessage(float message) {
    Debug.Log(message);
}

What will be printed if the animation event calls PrintMessage with parameter 42?

medium

A. Error: Missing parameter

B. PrintMessage

C. null

D. 42

Solution

1. Step 1: Understand the method behavior

   The method prints the float passed as the parameter to the console.

2. Step 2: Analyze the animation event call

   The event calls PrintMessage with 42, so Debug.Log prints 42.

3. Final Answer:

   42 -> Option D

4. Quick Check:

   Animation event calls method with 42 = prints 42 [OK]

Hint: Animation event passes parameter to method, which prints it [OK]

Common Mistakes:

• Assuming method name prints instead of parameter
• Expecting null if parameter is missing
• Thinking it causes an error without parameter

4. What is wrong with this animation event method?

private void TriggerEffect() {
    Debug.Log("Effect triggered");
}

medium

A. Method must be public to be called by animation events

B. Method has too many parameters

C. Method returns a value which is not allowed

D. Method name cannot start with a lowercase letter

Solution

1. Step 1: Check method access modifier

   Animation event methods must be public to be called by Unity's animation system.

2. Step 2: Analyze the method signature

   The method is private, so Unity cannot call it from an animation event.

3. Final Answer:

   Method must be public to be called by animation events -> Option A

4. Quick Check:

   Animation event methods = public access [OK]

Hint: Animation event methods must be public, not private [OK]

Common Mistakes:

• Using private instead of public methods
• Thinking method name casing matters
• Assuming return type causes error

5. You want to trigger a sound effect exactly when a character's foot touches the ground in an animation. How do you use animation events to achieve this?

hard

A. Use a coroutine to wait for the animation length then play sound

B. Add an animation event on the foot contact frame calling a public method that plays the sound

C. Add a script to the character that checks foot position every frame

D. Modify the animation clip to include the sound audio track

Solution

1. Step 1: Identify the correct use of animation events

   Animation events let you call code at exact frames, perfect for triggering sounds on foot contact.

2. Step 2: Apply the method

   Add an event on the frame where the foot touches ground, calling a public method that plays the sound effect.

3. Final Answer:

   Add an animation event on the foot contact frame calling a public method that plays the sound -> Option B

4. Quick Check:

   Animation event on frame triggers sound method [OK]

Hint: Place animation event on exact frame to call sound method [OK]

Common Mistakes:

• Using frame checks in Update instead of animation events
• Waiting full animation length instead of exact frame
• Embedding sound in animation clip instead of code