Perlin Noise (Flow Field)

Introduction

Perlin Noise scenes drive particles using a 2D noise field to create fluid-like motion, organic textures, and abstract visualizations. It is ideal for simulating wind, water, smoke, or generating generative art patterns.

Purpose of this guide: Help users understand the UI options, flow modes, and performance trade-offs for creating dynamic noise fields.

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Interface Overview

Controls are organized into three main panels in the Inspector (right sidebar):

1. Settings: Core simulation parameters (Particles, Noise, Flow Mode, Animation).
2. Appearance: Visual style (Trails, Accumulation Buffer, Palette).
3. Camera: Initial view settings (though Perlin Noise is typically 2D, it exists in 3D space).

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Configuration Details

1. Settings (Simulation)

• Particles:
  • Particle Count: Number of particles in the system. More particles = denser field but higher CPU load.
  • Preset: Quick configurations for common looks (e.g., "Soft Flow", "Swirl Vortex", "Crystal Grid", "Vector Drift").
• Noise & Flow:
  • Noise Step Size: How fast particles move each frame (spatial step).
  • Noise Scale: Zoom level of the noise map. Smaller values = large, smooth curves. Larger values = chaotic, tight details.
  • Flow Mode: Defines how noise controls movement:
    • ANGLE_FIELD: Noise value determines the angle of movement (0 to 360°). Standard Perlin noise flow.
    • VECTOR_FIELD: Two noise values determine X and Y velocity independently. Allows for complex, non-uniform movement.
    • SWIRL_FIELD: Adds a rotational force around the center, blending with the noise. Great for galaxy-like structures.
  • Angle Map: How raw noise is converted to angles:
    • LINEAR: Direct 1:1 mapping. Smooth and standard.
    • SOFT_POWER: Curves the distribution (pow(1.5)), biasing particles towards specific directional "channels" or "rivers".
    • QUANTIZED: Snaps angles to fixed steps (8 directions), creating geometric, circuit-board, or architectural patterns.
• Animation:
  • Flow Animation (time_scale): How fast the noise field itself morphs over time. Set to 0 for a static vector field.
  • Respawn Rate: Probability of particles resetting to a random position. Critical for preventing particles from getting stuck in "sinks" or loops.
  • Seed: Random seed for the noise generator. Change or randomize to get a completely different variation.

2. Appearance

• Style:
  • Dot Size: Thickness of the particle head.
• Trails:
  • Trail Lifetime: How long (in seconds) a trail segment persists. Warning: Values > 15s can consume significant memory.
  • Show Trails: Toggle trail rendering.
  • Fade Trails: If enabled, trails become transparent near the tail.
• Accumulation Buffer:
  • Use Accumulation Buffer: Alternative rendering technique. Instead of storing trail geometry, it draws particles onto a persistent texture that slowly fades.
  • Accumulation Fade: Controls how fast the previous frames fade out (0-255). Lower values = longer trails.
  • Note: This disables standard "Show Trails" and "Fade Trails" controls.
• Palette:
  • Defines the color gradient used by particles. Colors are assigned based on particle index.

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Performance & Best Practices

Goal	Recommended Settings
Fluid / Silk Effect	Accumulation Buffer ON, low Fade (~10-20), high Particle Count.
Geometric / Circuit	Angle Map = QUANTIZED, Step Size low.
High Resolution Video	Accumulation Buffer OFF, Trail Lifetime 2-5s.

Troubleshooting:

• Particles Stuck in Circles: Increase Respawn Rate or change Flow Mode to VECTOR_FIELD.
• Laggy Interface: Reduce Particle Count (e.g., < 20,000) or reduce Trail Lifetime.
• No Trails: If Accumulation Buffer is on, trails are drawn differently (check Accumulation Fade).

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