Unity Engine

Unity Fundamentals

Project Structure

• Assets Folder: Contains all project assets (models, textures, materials, scripts)
• Scenes: Individual levels or environments
• Prefabs: Reusable game object templates
• Packages: External libraries and tools via Unity Package Manager
• Project Settings: Global configuration for physics, graphics, input, etc.

GameObject Hierarchy

• Transform: Position, rotation, and scale of objects
• Parent-Child Relationships: Object hierarchy for organization and transformation
• Components: Modular functionality attached to GameObjects
• Tags and Layers: Organization and filtering for game logic

Unity Scripting and C# Basics

MonoBehaviour Lifecycle

• Awake(): Called when script instance is loaded
• Start(): Called before first Update frame
• Update(): Called once per frame
• FixedUpdate(): Called at fixed time intervals for physics
• LateUpdate(): Called after all Update calls complete
• OnDestroy(): Called when GameObject is destroyed

Common Unity APIs

• Transform: Access position, rotation, scale
• Rigidbody: Physics simulation
• Collider: Collision detection
• Renderer: Visual rendering control
• Animation: Animation playback control
• Animator: State machine for animations

Prefab and Component Architecture

Prefabs

• Creating Prefabs: Drag GameObject to Project window
• Prefab Variants: Inherit from base prefab with overrides
• Nested Prefabs: Prefabs containing other prefabs
• Prefab Mode: Edit prefabs in isolation
• Prefab Overrides: Apply or revert changes to prefabs

Components

• Mesh Renderer: Renders 3D meshes
• Mesh Filter: Holds mesh data
• Skinned Mesh Renderer: Renders animated meshes
• Animator: Controls animation playback
• Rigidbody: Physics simulation
• Collider: Collision detection

Unity Asset Pipeline and Addressables

Asset Import

• Model Import Settings: Scale, normals, tangents, animation clips
• Texture Import Settings: Compression, max size, mipmaps
• Audio Import Settings: Compression, load type, format
• Asset Bundles: Package assets for runtime loading

Addressables

• Addressable Assets: Load assets by address/label at runtime
• Asset Groups: Organize assets by build settings
• Content Catalog: Runtime database of addressable assets
• Asset Loading: LoadAsync for asynchronous loading
• Memory Management: Release and unload assets

Unity Optimization Techniques

Rendering Optimization

• Draw Call Batching: Combine similar objects into single draw call
• GPU Instancing: Render multiple instances with single draw call
• LOD Groups: Switch to lower detail models at distance
• Occlusion Culling: Skip rendering objects not visible to camera
• Lightmapping: Bake lighting for static objects

Performance Optimization

• Object Pooling: Reuse objects instead of instantiating/destroying
• Script Optimization: Avoid Update when possible, use coroutines
• Physics Optimization: Use fixed timestep, optimize colliders
• Memory Optimization: Use object pooling, avoid allocations in Update
• Profiling: Use Unity Profiler to identify bottlenecks

Unity Shader Graph and Visual Effects

Shader Graph

• Node-Based Shaders: Create shaders visually without code
• PBR Master Node: Physically based rendering
• Unlit Master Node: Non-physically based rendering
• Custom Properties: Expose parameters to material inspector
• Sub-graphs: Reusable shader logic

Visual Effects Graph

• Particle Systems: Create complex particle effects
• GPU Particles: High-performance particle simulation on GPU
• Event Contexts: Trigger events based on particle behavior
• Trails and Ribbons: Create trail effects
• Collision Detection: Particle collision with scene objects

Unity 3D Asset Integration

Model Import

• FBX Import: Import 3D models from Blender, Maya, etc.
• Scale Conversion: Handle different unit systems (cm vs m)
• Animation Clips: Extract and configure animation clips
• Rig Import: Import humanoid or generic rigs
• Material Generation: Auto-generate materials from model

Material Setup

• Standard Shader: PBR-based standard shader
• Shader Graph Materials: Custom shader graph materials
• Material Properties: Albedo, metallic, smoothness, normal maps
• Texture Slots: Assign textures to material properties
• Material Variants: Create material variations for different states