Stone cells

Good for

Organic vases, planters, terrain.

Print notes

• Depth 0.4 to 1.5 mm for a 0.4 mm nozzle (as written: 1.2 mm).
• Best on walls, printed upright. On a flat top, use thin layers (0.12 mm or less).
• Fade it out over the bottom 3 mm so the first layers are flat and stick to the plate.
• Not printed yet: these notes come from the geometry. The test cube will tell us more.

The formula

The real code this page runs: give it a point (U mm across, V mm up) and it returns the height there, in mm. Push the surface out by that much and the texture is real geometry.

function voronoi(U: number, V: number, p = 10.0, amp = 1.2) {
  const x = U / p;
  const y = V / p;
  const xi = Math.floor(x);
  const yi = Math.floor(y);
  let d1 = 9.0;
  let d2 = 9.0;
  for (const dx of [-1, 0, 1])
    for (const dy of [-1, 0, 1]) {
      const cx = xi + dx + rnd(xi + dx, yi + dy, 1);
      const cy = yi + dy + rnd(xi + dx, yi + dy, 2);
      const d = Math.hypot(x - cx, y - cy);
      d2 = d < d1 ? d1 : Math.min(d2, d);
      d1 = Math.min(d1, d);
    }
  return amp * clamp((d2 - d1) / 0.12, 0, 1) ** 0.7;
}

function clamp(x: number, lo: number, hi: number) {
  return Math.min(Math.max(x, lo), hi);
}

/** A repeatable random number 0..1 for a cell (no Math.random: the same texture every time). */
function rnd(a: number, b: number, k = 0) {
  const x = Math.sin(a * 127.1 + b * 311.7 + k * 74.7) * 43758.5453;
  return x - Math.floor(x);
}

Printed