We are no longer seeking applicants for this position.

We’re looking for a enthusiastic physics programmer interested in developing a system for handling planetary collisions (and collisions at other scales of objects) for the upcoming sequel to Universe Sandbox. This is a contract position, but has the potential to become more permanent.

You’ll be working with the creator of Universe Sandbox, our astronomer, the core game architect, the developer of our gravity integrator and smooth particle hydrodynamics tech, and aiding our graphics programmer. We are creating a robust, real time model for collisions of objects at all scales – asteroids, planets, moons, and stars (and smaller human sized objects) that works at wide range of time steps (including super slow motion). The collision system will need to work with variable numbers of spawned bodies and particles with smooth transitions between all states.

We want to create a system that will handle the Moon colliding with the Earth, the Earth colliding with Jupiter, Jupiter colliding with another gas giant, and something that works when a user decides to spawn a black hole inside of a moon.

You will oversee the integration of existing collision physics analytical and numerical solutions into one system that smoothly transitions between the handling of various cases, making sure that edge cases are accounted for.

Our continuing goal is to make the easiest and most captivating way to learn about the universe through real-time interaction, creation, and destruction… while keeping the simulation representative and true to our best understanding of reality.

Join a talented team and let’s make something amazing that’s never been created before.

In short: collisions must be amazing.


  • Physics programming experience
  • Love watching slow motion videos of collisions and explosions
  • Interest in helping change the way the world perceives our universe and fragile planet


  • Strong C# and Unity experience
  • Experience with rigid body physics systems like: PhysX, Jitter, or Bullet
  • Ability to meet in person at least once a week in the Capitol Hill neighborhood of Seattle, WA

Company Overview

Giant Army is the company behind Universe Sandbox, a space simulator that’s sold hundreds of thousands of copies on Steam. We’re based in Seattle, Washington, USA, but the team has members in Montana, Germany, and Denmark.

Product Overview

Universe Sandbox is our core product that lets the user explore and learn about our amazing universe while creating and destroying on a scale they’ve never before imagined. It’s more than a game; it’s a way of experiencing and learning about reality in a way that’s never been done before. The new version will be available for Windows, Mac, and Linux.


We are no longer seeking applicants for this position.

If you’re interested please email us at:
jobs at universesandbox.com

In the email please include a:

  • Relevant email subject
  • Answer to these two questions:
    – What is the most appealing part of this opportunity?
    – What aspect of physics simulations do you find most interesting?
  • Link to where you originally heard about this job posting
  • Link to or copy of your resume


Current State of Collisions and Development

We’ve been developing the sequel to Universe Sandbox in C# and Unity for 2 years. We have a great Open CL based gravity integrator and an analytical system in place for simple collisions that works fairly well. We have ideas for how to move forward with this, but there’s too much else for everyone to do for this critical feature to get the attention it needs. We’re open to new ideas and rebuilding the existing system to get the best end result.