Physion
Interactive Physics Simulations

What is Physion?

Physion is a browser-based 2D physics simulator. You draw shapes on a canvas, connect them with joints and springs, press play, and watch real physics take over. It is free to use, it runs in a normal web browser, and you do not need an account to start. Teachers use it for classroom demonstrations, students use it to see what the equations they are studying actually do, and hobbyists use it to build machines that would be impossible to build for real.

Unlike desktop physics sandboxes, Physion runs entirely in your browser, so there's nothing to download or install, and your scenes are playable on any device with a modern browser. Take a look at what others have built in the showcase.

One of the key features of Physion is its ability to create a wide range of interactive physics simulations using simple drawing tools. This means that users can easily create objects by drawing shapes such as rectangles, circles, polygons, regular polygons, and more. These objects can then be linked together using joint constraints such as axles, rods, pulleys, and springs to simulate real-world interactions.

To build a scene you need a desktop or laptop computer with a current web browser. Phones and tablets can open and watch any scene, but the drawing tools are switched off on them, so build your scenes on a computer. You only need an account if you want to save your own work, and you can create one with Google or Facebook.

Every simulation feature is available to everyone: the free plan runs the same engine and the same tools as the paid ones. Paid plans simply raise how many scenes you can save each month and remove ads. See the pricing page for the details.

For more information on how to use the app, please visit our docs page.

Key Features

• Create a variety of shapes (rigid bodies) within your Scene.
• Link objects together using joint constraints.
• Instantly simulate your creations.
• Perform boolean operations (union, difference, intersection).
• Simulate liquids and soft-bodies.
• Create particle emitters.
• Draw the forces acting on any body as labeled arrows (free body diagrams).
• Plot any property of a body over time on a live graph.
• Change physical properties (such as gravity, friction, density, spring constant, etc.) in the Property Editor.
• Use scripting (JavaScript) to enhance your creations with extra functionalities.
• Use the app in English, Greek, Spanish, Brazilian Portuguese, Vietnamese, or Czech.
• Web Application:
  • Runs directly in the browser (no download or installation required).
  • User creations (scenes) can be easily shared and viewed by others.

Soon to be added features

• Optics simulation (lenses and refraction).
• Custom UI components (e.g. sliders, buttons, etc.).

You can always suggest a new feature using our feature request page.