Open Paraplex

Generators

A generator is a layer whose shape comes from a small program: thousands of stars in spiral arms, a city of blocks, rolling terrain, a field of grass in the wind. Paraplex comes with five, each with settings you can animate. You can change their code, write your own, or ask the assistant to.

The five starters: Galaxy, City blocks, Terrain, Grass and Orbits

Add a generator

Click Generator in the dock for a Galaxy. Press and hold it to choose a starter:

StarterWhat it buildsIts settings
GalaxyStars in spiral arms, turning slowlyStars, Arms, Twist, Radius, Spin, Core and Rim colors
City blocksA grid of buildings of varied heightsBlocks, Height, Streets, Rise, Color
TerrainRolling hills of columns, driftingResolution, Scale, Height, Drift, Low and High colors
GrassBlades swaying in the windBlades, Wind, Height, Color
OrbitsSpheres circling on ringsRings, Per ring, Speed, Color, Paths

City, terrain and grass lie flat, like the ground. Tip them toward the camera with Rotation X to see their tops.

The Generator panel

Select a generator and its panel opens above the dock.

The Generator panel: Program, Seed with its dice, Edit code, Ask the assistant, and the program's settings, numbered
  1. Program: which starter it runs. Choosing another one replaces the code, so save any changes of your own first.
  2. Seed: a different random version of the same program. The dice button rolls a new one.
  3. Edit code opens the program's code.
  4. Ask the assistant… starts a message to the assistant to change the generator for you, like "make the arms thicker" or "add a second color".
  5. The program's settings. Each has a diamond, so you can animate it: a galaxy that unwinds, a city that rises.

The line under the program shows how many things it drew.

Change the code

Click Edit code to see the program.

The Generator panel with its code open, the code numbered, then Apply code and Revert
  1. The code. Edit it right here.
  2. Apply code runs your changes (⌘ Cmd+Enter).
  3. Revert goes back to the code as it was.

If the new code has a mistake, the layer draws nothing and the error shows under the program. Close code throws away changes you haven't applied.

How a program works

A program has two parts:

  • export const params lists the settings, each with a type (number, integer, color, choice or true/false), a default and a range. Each one becomes a control in the panel.
  • A default function gets the time, the settings, the seed and helpers for random numbers and noise, and returns what to draw: many copies of one shape (a box, sphere, card, dot, cylinder or cone), each with its own position, size, rotation and color, plus optional lines.
export const params = {
  count: { type: "integer", default: 200, min: 10, max: 2000, label: "Count" },
};

export default function generate({ time, params, random }) {
  const positions = [];

  for (let i = 0; i < params.count; i += 1) {
    // x, y and z for each sphere, one after another.
    positions.push(random() * 3 - 1.5, Math.sin(time + i) * 0.3, random() - 0.5);
  }

  return { instances: { shape: "sphere", positions } };
}

A program can draw up to 20,000 copies and 100,000 line segments, and must finish within 6 seconds. It runs walled off from the rest of the app.

Tip

The easiest way to get a program of your own is to describe it to the assistant: "a spiral staircase of cards", "rain falling on a grid". It writes the code, tests it, and adds the settings as controls.