Pedestrian simulator

Walky

See how a crowd moves through a space you draw.

Download on the App Store Try Walky Lite Check out the git repo

Built with love in Zurich, Switzerland 🇨🇭

Live — 160 pedestrians, routing themselves, right now.

Walky Go on the App Store

Three taps in, you have a crowd.

Free, on iPhone, iPad and Mac.

  1. App Store screenshot headed “Create — draw walls, set goals, add a crowd”. Walky Go on an iPhone: coloured rectangles on a pale ground with a teal crowd and a magenta crowd spreading between them, and the tool bar along the bottom.

    01 Trace a wall. The line closes into a shape the crowd cannot cross.

  2. App Store screenshot headed “Simulate — paint a crowd, press play, see what happens”. Walky Go on an iPhone: hundreds of yellow pedestrians streaming around four coloured walls on a black ground and funnelling into the gaps between them.

    02 Every Walky finds their own way, and rethinks it as you keep drawing.

  3. App Store screenshot headed “Explore — find routes and measure walking distances”. Walky Go on an iPhone: a yellow measured route bending around the walls between two points, labelled 26 metres on foot, 19 seconds.

    03 Tap two points for the walk between them, in real metres.

What it does

A room, a crowd, and no instructions.

Real maps

The city as your floor plan

Any address, straight from OpenStreetMap — life size, or down to 1:20.

© OpenStreetMap contributors (ODbL); ground by Apple.

Stickers

18 unique iMessage stickers

A Walky pedestrian cheering, captioned “Walky time!” A Walky pedestrian looking determined, captioned “Pathfinding intensifies!” A Walky pedestrian celebrating, captioned “Goal reached” A Walky pedestrian squashed in a crowd, captioned “So crowded” A Walky pedestrian stopped at a wall, captioned “Nope, wall” A Walky pedestrian lying down exhausted, captioned “Just one more simulation…”

Apple Intelligence Beta

Describe a place, get a map

A sentence in, walls out — laid out on device.

Room scan

Scan the room you are standing in

LiDAR, at life size. A doorway takes one person at a time.

AirPlay

Walky on the big screen

The map goes to the TV. The controls stay on the phone.

The algorithm

Draw the world

Dijkstra over a visibility graph, rebuilt every time you draw.

The crowd

Paint a crowd

Everyone picks their own next step, and heads for the goal the fastest way it can.

Share

One file, both apps

A .walky file holds the whole map — walls, crowd and settings — and the same bytes open in the browser. No server, either way.

The engine

Calibrated, not tuned.

The numbers come from the crowd-dynamics literature, not from turning knobs until it looked right.

  • 1.34 m/s

    Weidmann's free walking speed. The scale is anchored to a real body rather than to the screen: 56 pixels to the metre.

  • Dijkstra, re-priced

    Routes come from a visibility graph rebuilt from the geometry. The routing notices the crowd every two seconds and re-costs its edges by how long people are actually taking, so they go round their own queues.

  • Speed · density · flow

    The three numbers the pedestrian literature reports, measured live while it runs — so a run can be held against published data.

Download on the App Store Or try Walky Lite