Chapter 11: Effects and Particle Systems

Learning Objectives

1. Master the basic settings of the particle system
2. Learn to create effects like fire, smoke, and water splashes
3. Understand force fields and physics simulations
4. Master the hair and fur system
5. Learn crowd animation and instancing

11.1 Particle System Basics

Particle System Concept

• Particle System: A system for simulating a large number of small objects, such as raindrops, snowflakes, sparks, etc.
• Emitter: The object that generates particles
• Particle Lifecycle: Birth → Lifespan → Death

Particle System Types

1. Emitter: Emits particles from a surface
2. Hair: Creates hair and grass effects

Basic Settings

Properties Panel → Particle System Properties
- Type: Select particle type
- Emission: Control emission parameters
  - Number: Total number of particles
  - Frame Start/End: Emission time range
- Lifetime: Particle lifespan

11.2 Emitter Particle System

Emission Settings

• From:
  • Verts: Emit from vertices
  • Faces: Emit from faces
  • Volume: Emit from volume
• Random: Increase naturalness

Velocity Control

• Velocity:
  • Normal: Along the normal direction
  • Random: Random direction
  • Object: Along the object's axis
• Physics Type:
  • Newtonian: Newtonian physics
  • Keyed: Keyframe controlled
  • Boids: Crowd behavior

Render Settings

• Render As:
  • Object: Render as a specified object
  • Halo: Halo effect
  • Line: Lines
  • Path: Paths

11.3 Creating Common Effects

11.3.1 Fire Effect

1. Create an emitter plane
2. Add a particle system
3. Set emission parameters:

   Number: 1000
   Lifetime: 60
   Velocity → Normal: 5
   Random: 2

4. Physics settings:

   Physics Type: Fluid
   Settings → Density: 0.1

5. Force field settings: Add an upward wind force

11.3.2 Smoke Effect

1. Use Quick Effects → Smoke
2. Adjust domain settings:

   Domain → Resolution: 64
   Density: 0.5
   Temperature Diff: 1.0

3. Emitter settings:

   Flow Type: Smoke
   Density: 2.0

11.3.3 Water Splash Effect

1. Create a water surface and a collider
2. Set up the particle system:

   Physics Type: Fluid
   Fluid → Stiffness: 0.8
   Viscosity: 0.2

3. Material settings: Transparency and reflection

11.4 Force Field System

Force Field Types

1. Force: Constant directional force
2. Wind: Wind effect
3. Vortex: Rotational force field
4. Magnetic: Magnetic attraction
5. Turbulence: Random disturbance

Force Field Properties

• Strength: Force field strength
• Flow: Affects particle flow
• Noise: Adds randomness
• Absorption: Degree to which particles are absorbed

Collision Settings

Object Properties → Physics Properties → Collision
- Enabled: Enable collision
- Damping: Damping coefficient
- Friction: Friction force
- Permeability: Permeability

11.5 Hair System

Basic Hair Settings

1. Select the object, add a particle system
2. Set Type to Hair:

   Hair Length: 1.0
   Segments: 5
   Children → Type: Simple
   Display Amount: 50%

Hair Styling

1. Comb:
   • Switch to Particle Edit mode
   • Use the comb tool to adjust direction
2. Cut:
   • Adjust hair length
3. Add:
   • Increase hair density

Hair Material

Shader Editor → Hair BSDF
- Color: Hair color
- Roughness: Roughness
- Radial Roughness: Radial roughness
- Coat: Glossy coat
- IOR: Index of Refraction

11.6 Crowd Animation and Instancing

Boids System (Crowd Behavior)

1. Set particle physics type to Boids:

   Physics Type: Boids
   Boids → Rules:
   - Goal: Goal-oriented
   - Avoid: Avoid collision
   - Crowd: Flocking behavior
   - Center: Centering

Instancing Techniques

1. Object Instancing:

   Render → Object: Select instance object
   Scale: 1.0
   Scale Randomness: 0.2

2. Collection Instancing:
   • Create an object collection
   • Reference the collection in the particle system

Animated Instances

Render → Extra:
- Whole Group: Use the entire group animation
- Use Count: Limit the number of instances

11.7 Particle System Optimization

Performance Optimization

1. Display Optimization:

   Viewport Display:
   - Display: Lower the display percentage
   - Show: Display only a portion of particles

2. Render Optimization:
   • Use the Children system to increase density
   • LOD (Level of Detail) settings

Cache Management

Cache → Disk Cache:
- External: Use external cache
- Index: Cache index
- Compression: Compression options

11.8 Advanced Effects Techniques

Particle Inheritance

• Inherit:
  • Location: Inherit location
  • Rotation: Inherit rotation
  • Scale: Inherit scale

Dynamic Paint

Dynamic Paint:
- Canvas: Canvas settings
- Brush: Brush settings
- Effects: Effect types

Fluid and Particle Combination

1. Create a fluid domain
2. Use particles as a fluid source
3. Adjust interaction parameters

Practical Exercises

1. Create a campfire effect (fire + smoke + sparks)
2. Create a rainy day scene (raindrops + splashes + fog)
3. Design an explosion effect (debris + smoke + shockwave)
4. Create a grass effect (hair system)
5. Create a flock of birds animation (Boids system)

Key Takeaways

• Particle systems are suitable for simulating a large number of similar objects
• Reasonable physics parameter settings can achieve realistic effects
• Force field systems can create rich dynamic effects
• The hair system is not only for hair but can also create various fiber effects
• Crowd animation can simulate natural flocking behavior
• Optimization settings are crucial for complex particle systems

Next Chapter Preview

The next chapter will cover physics simulation and dynamics, including advanced physics effects like rigid bodies, soft bodies, cloth, and fluid simulations.