Principia

Principia is a free and open source physics-based sandbox game. In Principia, you can build contraptions and simulate them in the physics simulation. This could be a mechanical contraption, an RC car, or a pinball game. Principia also contains a LuaScript object which allows you to write and create Lua programs that can interact with and affect the simulation.

Principia consists of different types of levels, available to choose from in the sandbox or on the community site:

• Custom levels allow you to create anything, with or without goals. You can create score-based minigames and let players compete for the highscore, or just build a vehicle which players can crash into with satisfying destruction physics.
• Adventure levels where you take control of a miniature robot which can do whatever you decide it to do in the sandbox. It can take part in a giant battle with enemy robots, or it can explore a procedurally generated terrain made available for you to do anything within.
• Puzzle levels where the player is given the ability to move objects around and construct their own contraptions to solve a puzzle, whether it be guiding robots to the goal or any other goal you can think of.

The Principia sandbox gives you access to 200+ different objects ranging from basic wooden building blocks to advanced logic circuits you can wire together with the game's circuitry system.

There are tens of thousands of user made creations by the community to play and enjoy. Browse the latest that the community has made right now, or browse the full collection of 25000+ levels from 2013 to 2018 on the Principia official community site archive. You can also watch a collection of showcase videos of community levels, showing off interesting creations.

Principia began its life in 2013 as a paid game for Android and later Windows. It has now become an open source project with the source code available on GitHub and has expanded to being available on additional platforms such as Linux, Haiku OS, macOS and the Web. Be sure to check out Principia community site where user-created levels are uploaded for others to play and enjoy.

Want to try Principia without installing anything? Try the new and experimental Principia web version!