Spot Noise*

Introduction
Key Features
Parameters
Quick Recipes

Spot Noise is a procedural 3D cellular noise that generates smooth, isotropic spots by measuring the distance to the nearest randomly seeded point in space. While it shares the same underlying cellular logic as Dent Noise, Spot Noise focuses on additive layering and color blending. Each cell contributes a soft exponential falloff shaped by density, scale, and bias controls, while optional blue-noise decorrelation removes grid artifacts for a more natural, organic look.

Performance Cost 🟢 Low

Space 2D/3D - UV/World/Object

Implementation Native Compiled C++

Devices (Cycles) CPU / GPU (1:1)

Usage & Behavior

Default values

Multi octaves

With fading enabled

Clustered spots by mapping density parameter

This noise is ideal for creating patterns that require distinct "features" scattered across a surface. Unlike gradient noise which is continuous and wavy, Spot Noise creates discrete islands of intensity. With the Decorrelated type enabled, it avoids the accidental clustering of points common in standard noise, producing a pleasingly uniform distribution similar to Poisson-disk sampling.

Best Used For: Animal fur patterns (leopard/cheetah), mold and lichen growth, organic cell structures, stippling effects, and random surface oxidation.

Key Features

Cellular Distance: Generates isotropic features based on nearest-neighbor distance.
Decorrelation: "Blue Noise" option prevents unsightly clustering of spots.
Fractal Layering: Built-in octaves allow for complex, dirty, or variable-sized spots.

Parameters

Type Enum

Selects the seeding algorithm:

WHITE: Standard pseudo-random seeding. Fast, but spots may randomly clump together or leave large gaps.
DECORRELATED: Uses a blue-noise/low-discrepancy distribution. Spots are spaced more evenly, creating a more natural and organic look.

Normalize (bool, default: true)

When enabled, the final output intensity is normalized based on the total amplitude of the octaves. This ensures the result stays within a predictable 0-1 range regardless of how many layers are added.

Coords Vector

The input texture coordinates.

Scale Vector (default: 2.0, 2.0, 2.0)

Global scaling factor. This defines the underlying grid size; larger values mean smaller cells (and thus smaller/more numerous spots).

Spot Color Color

The RGB color tint applied to the spots. The noise outputs a color result, blending this color onto black based on the spot intensity.

Spot Density (default: 0.32)

Controls the "tightness" of the spot gradient. Higher density makes the falloff steeper, resulting in sharper, more contained spots.

Spot Scale (default: 1.0)

Controls the radius of the spots *relative* to the cell size.
- High values: Spots grow and may merge.
- Low values: Tiny, isolated dots.

Spot Bias (default: 0.25)

Adjusts the gamma/contrast of the spot falloff. Modifying this changes the visual "softness" of the spot center.

Spot Fade (default: 0.1)

Controls the blending curve of the spot color. Higher values fade the spot out more aggressively, leaving only the very center visible.

Octaves (default: 1)

The number of fractal layers. Adding octaves layers smaller spots on top of larger ones.

Octaves Amplitude (default: 0.25)

The strength of each subsequent octave (Persistence).

Octaves Size Var (default: 2.1)

The frequency multiplier for each octave (Lacunarity).
- > 1.0: Subsequent layers are smaller (standard detail).
- < 1.0: Subsequent layers are bigger (creates patchy, cloud-like variance).

Quick Recipes

Use these settings for biological and organic patterns.

Leopard Skin

Scale: 3.0
Octaves: 2
Oct. Size Var: 0.6
Spot Density: 0.4

Using a Size Var < 1.0 layers larger patches over smaller ones, creating varied animal markings.

Surface Mold

Type: DECORRELATED
Spot Fade: 10.0
Spot Bias: 0.1
Octaves: 3

Decorrelated distribution ensures natural growth; high fade keeps the spots soft and fuzzy.

Porous Rock

Scale: 10.0
Spot Density: 0.2
Spot Scale: 1.5
Octaves: 1

High scale and spot scale create a dense, overlapping lattice of holes.

Technical Note: The brightness of each spot is calculated using exp(-distance * density * 10.0). The Decorrelated mode uses a blue-noise hashing function which significantly reduces the variance in distance between neighboring points, solving the "clustering" issue inherent in random white noise.

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