# Arranging objects in 2D and 3D

──── 4 mins

No matter how many (thousand) times you wrote a particular piece of code, you *always* have to it look up. I’ve been there so many times.

My brain forgets most snippets that involve lots of `Math.sin`

and others. Anything like `((2 * i) / numItems) * PI`

. Unfortunately, that’s what a lot of “creative coding” is about.
Fortunately, my brain can do association, like “I know I wrote this code in *that* project.”

I now have too many creative code algorithms across too many projects. So I’ve collected them in this article.

All snippets are language-agnostic, framework-agnostic and valid JavaScript.

## 2D

### Arrange in a 2D grid

```
// arrange items in a horizontal grid from left to right
let gridSize = 3;
let itemSize = 60;
let numItems = 11;
for (let i = 0; i < numItems; i++) {
// from left to right
let gx = i % gridSize;
let gy = Math.floor(i / gridSize);
// swap gx and gy to arrange in a vertical grid from top to bottom
// gx = Math.floor(i / gridSize);
// gy = i % gridSize
let x = gx * itemSize;
let y = gy * itemSize;
// 4px spacing
rect(x, y, itemSize - 4, itemSize - 4);
}
```

### Arrange in a circle

```
let numItems = 8;
let radius = 100;
for (let i = 0; i <= numItems; i++) {
// I love this line
let angle = ((2 * i) / numItems) * Math.PI;
let x = Math.cos(angle) * radius;
let y = Math.sin(angle) * radius;
ellipse(x, y, 20, 20);
}
```

### Arrange on a half circle

```
let numItems = 7;
let radius = 100;
// use this value to offset the angle and rotate your semicircle
let angleOffset = 0;
for (let i = 0; i < numItems; i++) {
let t = i / Math.max(1, numItems - 1);
let angle = Math.PI * t + angleOffset;
let x = Math.cos(angle) * radius;
let y = Math.sin(angle) * radius;
ellipse(x, y, 20, 20);
}
```

### Make a spiral

```
let turns = 3; // How many revolutions
let radius = 100;
// How close we want the points to be, as an angle in radians, smaller is closer
let tightness = 0.2;
let full = Math.PI * 2 * turns;
for (let angle = 0; angle < full; angle += tightness) {
let r = radius * (angle / full);
let x = Math.cos(angle) * r;
let y = Math.sin(angle) * r;
ellipse(x, y, 4, 4);
}
```

## 3D

### Random points on the surface of a sphere

```
let radius = 100;
for (let i = 0; i < 1000; i++) {
// random θ and φ — spherical coordinate stuff 🤷♂️
let theta = random(0, Math.PI * 2);
let phi = random(-Math.PI / 2, Math.PI / 2);
let x = radius * Math.sin(theta) * Math.cos(phi);
let y = radius * Math.sin(theta) * Math.sin(phi);
let z = radius * Math.cos(theta);
point(x, y, z);
}
```

### Random points *in* a sphere

```
for (let i = 0; i < 1000; i++) {
let phi = Math.random() * (2 * Math.PI);
let costheta = Math.random() * 2 - 1;
let u = Math.random();
let theta = Math.acos(costheta);
// Math.cbrt is part of ES2015
let r = radius * Math.cbrt(u);
let x = r * Math.sin(theta) * Math.cos(phi);
let y = r * Math.sin(theta) * Math.sin(phi);
let z = r * Math.cos(theta);
point(x, y, z);
}
```

### Create a cube of cubes!

```
let xCount = 4;
let yCount = 4;
let zCount = 4;
let boxSize = 20;
for (let k = 0; k < zCount; k++) {
for (let j = 0; j < yCount; j++) {
for (let i = 0; i < xCount; i++) {
let size = boxSize + 7; // add a bit of spacing around each cube
let halfWayX = (size * xCount) / 2;
let halfWayY = (size * yCount) / 2;
let halfWayZ = (size * zCount) / 2;
if (xCount % 2 != 0) halfWayX -= size / 2;
if (yCount % 2 != 0) halfWayY -= size / 2;
if (zCount % 2 != 0) halfWayZ -= size / 2;
let x = size * i - halfWayX;
let y = size * j - halfWayY;
let z = size * k - halfWayZ;
box(x, y, z, boxSize, boxSize, boxSize);
}
}
}
```

If you’re curious how these images were generated, the code is available in this repository.

Suggestions welcome! I want to keep updating this post with cool visuals, and I would love your help. Please keep suggestions to spatial stuff though. We collectively wrote enough bubble sorts.