Noise and patterns
Every noise and pattern field, what it looks like, and its parameters
Construct has procedural noise and pattern fields. Each is a definition record in the Fields family, so the Things finder lists them, and you place one like any other definition. They come in three groups:
- Noise holds the bare noise algorithms: each one is a published method, such as Perlin noise or fractional Brownian motion.
- Patterns holds the bare structures: rings, bricks, cells, waves.
- Looks holds artistic recipes that combine the two, such as wood or marble. Each look matches the look of a texture in another program.
A field gives a number at every point:
- As geometry, the number is the distance, so a noise field makes a surface of its own, or shapes another one through an operator.
- As a material pattern, the number drives a channel of a material, for example the color through a gradient. Materials with patterns come in a later release.
The noise bases
Each basis is one kind of noise, summed over octaves. They share seven parameters:
| Parameter | What it does |
|---|---|
| Frequency | Cells per unit length of the first octave |
| Seed | Another whole number gives another noise with the same look |
| Octaves | The number of octaves. A fraction fades the last one in, so a drag is smooth |
| Lacunarity | The frequency of each octave over the one before. 2 doubles it |
| Gain | The amplitude of each octave over the one before. 0.5 halves it |
| Fractal | How the octaves add up: one of the six fractal types below |
| Phase | Animates the noise. Drive it with an expression such as =time * 0.2 |
| Basis | Looks like | Its own parameter |
|---|---|---|
| Value noise | Soft blobs. At smoothness 0, squares of random gray | Smoothness |
| Perlin noise | The classic smooth noise | Period: repeats the noise every that many cells, for a seamless tile |
| Simplex noise | Like Perlin, with fewer grid marks | Flow: turns the gradients, so an animated flow swirls in place |
| Worley noise | Cells. F1 is the distance to the nearest point, F2 ā F1 draws the walls between cells | Feature (F1 to F2 ā F1), and Metric in place of Fractal: Euclidean, Manhattan or Chebyshev |
| Alligator noise | Overlapping bumps of random height | Falloff: the radius of each bump |
| Sparse convolution noise | Many small random bumps | Density: bumps per cell, 1 to 4 |
The fractal types
The Fractal parameter picks how the octaves add up. Each type is an algorithm of F. Kenton Musgrave (Texturing and Modeling, 3rd edition, chapter 16). A search for the name of a type finds every basis.
| Type | How the octaves add up | Other programs call it |
|---|---|---|
| fBm | The sum of the octaves: fractional Brownian motion | FBM, fBm Noise |
| Ridged multifractal | Sharp crests where the noise crosses zero, with the detail on the crests | Ridged MultiFractal |
| Hetero terrain | Each octave scaled by the height so far: smooth valleys, rough peaks | HeteroTerrain, Terrain |
| Hybrid multifractal | As hetero terrain, with the scale capped at 1 | Hybrid-MultiFractal, Hybrid terrain |
| Turbulence | The sum of the absolute values of the octaves: a crease at every zero | Turbulence, Turbulent Noise |
| Multifractal | The product of the octaves: a low octave damps all the ones above it | MultiFractal |
A fraction between two types blends them. LightWave's Increment (H) is the same control as Gain: Gain = Lacunarity^(āH). For example, H = 1 at Lacunarity 2 is Gain 0.5.
The looks
A look recreates the look of a texture from another program. Those programs publish names and parameters, not algorithms, so each look is built from the bare fields here and matched by eye. A search for the other program's name finds the look.
Looks of Cinema 4D noises
| Field | Cinema 4D name | Looks like |
|---|---|---|
| Box noise | Box Noise | Smooth, square-looking blobs with little detail |
| Blistered turbulence | Blistered Turbulence | Fine lights and darks, almost mineral |
| Plateau terrain | Buya | Mountains with flat plains between them |
| Cell noise | Cell Noise | Squares of random gray, with a soft edge |
| Puffy cells | Cranal | A round raised bump in every cell |
| Dents | Dents | Twisted, layered dents |
| Displaced turbulence | Displaced Turbulence | Soft structures that drift, for dunes |
| Electric | Electric | Thin bright filaments |
Looks of LightWave textures
| Field | LightWave name | Looks like | Built from |
|---|---|---|---|
| Wood | Wood | Sharp rings, pushed by turbulence | Rings, turbulence, a ramp |
| Soft wood | Wood 2 | Soft rings with a movable transition | Rings, fBm |
| Marble | Marble | Thin veins across an axis | A sine across the axis, distorted by fBm |
| Crackle | Crackle | Cracked cells, like dry skin or asphalt | Worley F2 ā F1, with fBm detail |
| Crumple | Crumple | Crumpled facets, choppy water | Worley F1 over octaves |
| Crust | Crust | Crossing circular rims | A rim around each Worley point |
| Veins | Veins | Thin veins along cell walls | Worley F2 ā F1 |
| Underwater | Underwater | Interlocking bands of light | Ripples at two wavelengths |
| Flakes | Flakes | Chips of random gray | One random value per Worley cell |
LightWave's other textures are bare fields here: its fractal textures are the fractal types above, and Bricks, Checkerboard, Dots, Grid, Honeycomb and Ripples are patterns.
The patterns
Patterns give the structure that noise then disturbs.
| Pattern | Value | Use |
|---|---|---|
| Rings | Bands around an axis | Wood rings. Warp them with Domain warp for grain |
| Strata | Bands along an axis | Rock layers and sediment |
| Waves | Ripples around a point | Water, brushed metal |
| Checker | Alternating cells, with a soft edge | Tiles and test patterns |
| Bricks | A brick bond in 3D, with mortar joints and a soft edge | Walls, paving |
| Honeycomb | Hexagonal cells with walls, extruded upward | Tiles, meshes |
| Dots | A ball in every cube of a grid | Perforations, studs |
| Grid | The lines of a cubic grid | Tiles, graph paper |
| Ripples | Waves from up to 8 random centers, crossing each other | Water |
Rings and Strata have a Profile: 0 is a smooth band, 1 a sawtooth.
Operators for noise
| Operator | What it does |
|---|---|
| Domain warp | Moves each point by a value noise per axis before its child |
| Gradient warp | Moves each point along the slope of simplex noise, so features drift along it |
| Noise displacement | Moves a surface in and out by value noise |
| Noise shape | Shapes a noise: fold, bias, gain, complement and an output range |
As geometry
A ray marcher steps by the distance a field gives, so a field must not change faster than it declares. Each field declares its steepest slope, and the marcher divides its steps by it. A field with a hard edge has an Edge, Bevel, Softness or Contrast parameter: a harder edge looks crisper and makes the field slower to march as geometry. As a material pattern the edge costs nothing.
The noise of a scene is the same on every computer: the hash is integer arithmetic, which the processor and every graphics card compute alike.