Unity Animation Techniques

Game Programming - Lecture 10

• Lecture delivered by Dr. Eman Abdellatif
• Focus on 3D games
• Agenda includes animation (3D game programming concepts)
• Revision of last session, scene graph covered

Scene Graphs

• 3D engines use scene graphs to manage and track 3D objects in a virtual world
• Nodes in the graph represent entities like 3D models, sounds, lighting.
• Group nodes (ovals) contain information about themselves and point to other nodes
• Leaf nodes (rectangles) contain only information about themselves
• Not all information is in every node
• Common entity types include 3D shapes, sounds, lights, viewpoints, and event triggers.

Basic Elements of Game Animation

• Aesthetics (the visual aspects)
• Mechanics (procedures and rules)
• Technology (materials and interactions)
• Story (sequence of events)

Types of Animation

• 2D animation
• 3D animation

2D Animation

• Creates the illusion of movement using a series of frames
• Measured in frames per second (fps)
• 24-30 fps: full-motion (Game Maker uses 30)
• 15 fps: full-motion approximation
• 7 fps: choppy
• 3 fps: very choppy
• Fewer than 3 fps: slide show

Popular Forms of Animation

• 2D animation (classical)
• Flash animation
• 3D animation
• Claymation (Stop-Motion)

2D Animation (Traditional)

• Animation done using a 'flipbook'
• Drawings can be shot onto film and projected
• Can be shot onto video and played on video players
• Can be recorded onto a computer to be played back later.

Motion Line

• Each frame is a drawing or image that slightly differs from the previous one.
• Rapid succession creates the illusion of motion
• Lines are invisible but represent the movement of an object, with location related to the centre of gravity
• Examples include a bullet flying straight up and down if bouncing, or human movement.

Key Frames

• Efficient way to create animation
• Advanced artists create key poses or key frames for characters.
• Beginner animators fill in motion between poses.
• Extreme positions, like wings up or down are easy to notice
• The more key poses the better the smoother animation
• Takes longer to develop, and may result in errors

In-Between Frames

• Frames created to smoothly transition between key frames
• Important for smooth animation
• Software often allows duplication for efficiency.
• Example of animation sequence using key figures

Frame Animation Guidelines

• Table listing various actions with minimum and maximum frame counts

Steps in Creating Animation Sequences (3 Parts)

• Concept of animation, visual representation

• Decide on the object's behaviour (e.g., animated once or continuously)

• Choose a grid size, constraints for the object

• Estimate number of in-between frames needed.

• Testing each animation and addressing flaws.

Sprite Animation

• Animated clips for 2D assets
• Various methods to create
• Sprite sheet (grid of Sprites) converts into animation
• Keyframing in Unity can also be used

What is a Sprite?

• Small graphic image
• Stored in off-screen video RAM
• Can be read from video RAM, copied to screen with 'BitBlit'.
• Sprites sync with vertical retrace in order to support multiple animations in a single array

Creating Sprite Animations Using Sprite Sheets

• Images with sequential sprites, similar to flipbooks
• Sprite Atlases for non-sequential sprites
• Optimizing 2D games by compressing sprites into a single image
• Keyframe animation used to animate the sprites
• Sprite Mode 'Multiple' necessary for animation extraction using the Sprite Editor and Slicing Tool.

Creating Sprite Animations in Unity

• Using the Unity software
• Import settings (sprite mode) are essential

Sprite Animation Sample 1

• Image/Graphic example

2-Sprite Editor

• Using the Editor tools
• Selecting the edit button opens a new window allowing direct manipulation
• Example illustrated with image/graphic

3- Slice Sprite Sheet

• Tool to slice sprites/images into individual sprites for animations
• Organized sprites are beneficial

Creating Sprite Animations from Selected Sprites

• Drag and dropping sliced sprites into the scene
• Selecting sprites directly from files/assets into the scene/project
• Unity will generate an animation clip and an animator.

Creating Keyframes Animation

• Selecting necessary animation folder
• Demonstrating animation process via steps in figure

Create New Clip

• Method of creating a new animation clip

Unity uses Automatic Keyframing

• Automatic recording and implementation of keyframes if needed
• Animation recordings in the animation window
• Pressing record to start recording

Blending your Animations with Animator

• Creating different actions for an animation clip
• Demonstrating using an animator

Sprite Animation Sample 2

• Image example of Pac Man as a sprite.
• Filling the sprite with colours, and shapes
• Creating multiple sprite arrays for different movements (right, down, up)

Multiple Sprite-Arrays

• Examples include different movements (right, down, up) for Pac-Man.

2D Sprite System

• Set of image sequences simulating 2D object movement
• Playback of image sequences (animation) to demonstrate movement
• Illustration of the sprite and associated clip

The 12 Laws of Animation

• Squash and Stretch
• Anticipation
• Staging
• Straight Ahead and Pose-to-Pose
• Follow Through and Overlapping Action
• Slow-Out and Slow-In
• Timing
• Exaggeration
• Solid Drawing
• Appeal

Squash and Stretch (S&S)

• Principle of a contrasting change in shape (from squash to stretch)
• Applying to moving figures
• Creates realism in animation
• Key example is a bouncing ball
• Not always essential to realism and can even be avoided for a humorous effect

How to Master Squash and Stretch

• Do not overdo squash and stretch (S&S)
• Maintain the feel over the visual
• The feeling of movement more than the visual.

Maintaining/Preserving Volume

• Objects' volume should not dramatically change during S&S
• Computer graphics can preserve volume accurately, but this may not look visually correct to the eye.
• Adjustment and fine-tuning may be necessary

Video-1 and Video-2

• Examples illustrating different concepts in the 12 Laws of Animation

Staging

• Scene setup drawing the viewer's attention
• Camera angles, colors, and movement are key factors
• Avoid cluttering animation
• Hayao Miyazaki is an example of great staging

Straight Ahead and Pose-to-Pose

• Drawing each frame sequentially
• This technique is useful for very fast movements or scenes of high excitement
• Key drawings used in pose-to-pose
• Assistants would complete the animation.

Follow Through and Overlapping Action

• Animated body parts move at different speeds and times
• Some parts lead the action (e.g., legs start running, then upper body follows)
• Creates realism in animation, and avoids a rigid robotic movement

Slow-Out and Slow-In

• Animation drawing more frames near beginning and end of an action for effects

Test your knowledge on Unity animation techniques, including the use of Sprite Sheets, Sprite Atlases, and principles like anticipation in animation. This quiz explores various aspects of character movement and animation principles essential for game development in Unity.