drapedFolds

The height of a draped cloth at a point: rounded ridges running along one direction, each rippling and swaying along its length, gathered where the cloth is pinned.

drapedFolds(
  coords: {along: Expr | number; across: Expr | number},
  folds: Fold[],
  opts: DrapeOptions,
): Expr

Import noise from shaders/std and use noise.drapedFolds.

coords come from a directionFrame: along runs 0 at the pinned edge to 1 at the free edge, across is the distance across the drape in the units foldSet laid the folds out in. ripple.waves is a wavyLine wave list each spine wanders by (every fold starts at its own phase) and ripple.gain scales it. sway moves all the folds together on the clock, like a breeze. swell makes each ridge rise and fall along its length so neighbours merge and part. pinning (0–1) gathers the folds at the pinned edge: narrow and still there, wide and free at the far edge. sharpness (default 2) is how tightly the ridge falls away and crease (0–1, default 0) flattens its crest into a plateau that meets the next fold in a tight valley: 0 is a round bell, 1 a flat face with a sharp crease. The result is a height in the units of each fold's height. Take its slope with fdSlope or fdCurvature for relief.

Parameters

Example

const cloth = (at: Expr) => drapedFolds(drape.coordsOf(at), folds, {time: t, ripple: {waves: RIPPLE}, sway: {amount: breeze}, pinning: u.pinning})
const relief = fdCurvature(cloth, q, 0.004)

Tip. Keep the wave list and swell as constants next to the definition. They are the look.

See also

• foldSet — Lays out the ridges of a draped cloth: count folds spread evenly across spread, each nudged sideways, widened and raised by a seeded amount so no two are alike.
• wavyLine — The height of an animated wavy line at a point along it: a stack of traveling sines.
• fdSlope — The value and slope of any field at a point: value, dx and dy.

Used by

Satin