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MotionAtelier

Noise

Noise travels from the first key to the second through a set of random offsets, smooth or jagged, and always lands exactly on both keys. The same seed always gives the same shape.

Noise with default parametersThe value moves from 0 to 1 through eight irregular segments, wandering above and below the straight path, smoothly rounded.
Noise, default parameters (Frequency 8, Amplitude 0.20, Seed 1, Smooth 0.75). Plotted from MotionAtelier 0.4.2's own curve code, outside Houdini. An illustration of the curve, not a screen capture.

Use it

Section titled “Use it”
  1. Set SHAPE ▸ Noise.
  2. In the Motion Stack tab, set Frequency, Amplitude, Seed and Smooth.
  3. Preview, select the keys in Houdini, and press Commit Keys.

Try other Seed values until the pattern reads well; the result for a given seed never changes.

Parameters

Section titled “Parameters”
ControlRangeDefaultWhat it changes
Frequency1 to 64
slider to 32; type larger values		8Random offsets across the span. The span is divided into this many equal cells, with one key per cell boundary: Frequency + 1 keys per interval.
Amplitude0.00 to 1.00
slider to 0.50; type larger values		0.20Largest offset from the straight line between the ends. In units of the whole move. Offsets taper to zero towards both keys, so they are largest in the middle.
Seed0 to 2147483647
slider to 100; type larger values		1Pattern number; the same seed gives the same shape.
Smooth0.00 to 1.000.75How rounded the transitions between offsets are. 0 gives straight segments with sharp corners; 1 gives fully rounded transitions.
Noise with Smooth 0 and Smooth 1The same random offsets: with Smooth 0 they are joined by straight lines with sharp corners; with Smooth 1 by rounded curves.
  • Smooth 0
  • Smooth 1
The same seed with Smooth 0 (solid, jagged) and Smooth 1 (dashed, rounded). Plotted from MotionAtelier 0.4.2's own curve code, outside Houdini. An illustration of the curve, not a screen capture.
Noise with two seedsTwo different random patterns with the same frequency, amplitude and smoothness.
  • Seed 1
  • Seed 2
Changing only the Seed gives a different pattern with the same character. Plotted from MotionAtelier 0.4.2's own curve code, outside Houdini. An illustration of the curve, not a screen capture.

Behaviour

Section titled “Behaviour”
  • Deterministic. The offsets come from a fixed hash of the seed, so a recipe or history entry reproduces exactly, on any machine.
  • Exact ends. The first and last key are reached exactly; the offsets taper to zero towards them.
  • Sparse. The committed keys are the noise itself (Frequency + 1 per interval), not a sampled approximation.
  • Needs a move. Like Wave, Noise varies around the path between two different values. On two equal keys the interval is written flat; see Equal end values. To add noise to motion of any shape, use the Noise effect in the Motion Stack instead.

Factory recipes

Section titled “Factory recipes”
Recipe Frequency Amplitude Seed Smooth
Subtle Jitter 8 0.08 1 0.80
Handheld 12 0.20 42 0.65
Rough Shake 16 0.25 7 0.20
Section titled “Related”
  • Wave: regular instead of irregular variation.
  • Motion Stack: the Noise effect works on top of any shape.