Flow Field Generator

How the Flow Field Generator works

Flow field generator: how it works

Every point on the canvas has an angle assigned to it. The angle is read from a Perlin noise function, so neighbouring points have similar angles and the field changes smoothly across the picture. A particle starts at a random position, looks up the angle under it, takes a small step in that direction, and repeats. Because the field is smooth, the path is smooth; because the field is random, no two regions look alike.

Field scale sets how quickly the angles change across the canvas. At 1 the field is broad and the lines sweep across the whole picture in long arcs. At 10 it changes every few pixels and the lines curl into tight scribbles. Around 3 gives the classic wind-blown look.

Turbulence multiplies the angle range. At 1 the arrows only swing through part of a turn and the lines all drift roughly the same way, like grass in wind. At 5 or more they can point anywhere, so lines loop back on themselves and form eddies.

Density is the number of particles, from about 120 to 1,200. Low values show individual strokes on the ground colour; high values fill the canvas into a woven texture. Line length is how many steps each particle takes before it stops. Short lines look like fur or brush marks; long ones look like hair or smoke. Line weight widens the strokes and adds variation between them.

Palettes each have a ground and four line colours. Each line picks one at random and is drawn semi-transparent, so where lines cross the colours build up. Ink is a light-ground palette for a pen-plotter look; the others are dark grounds for wallpapers.

Export. Save PNG re-runs the whole simulation at the chosen resolution with the same seed. The step size scales with the canvas so the composition matches the preview; a 4K export with density 10 and length 10 takes a couple of seconds.

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