Riemann is a 3D Geometry Processing / Collision Detection / Physics Engine with zero dependencies. This is a personal learning project, I want to write my own physics engine to understand some of the key algorithm that makes a physics engines works.

This project is named after the 19th-century German mathematician Bernhard Riemann, who invented Riemannian geometry and the concept of manifold.

Rigid Body Dynamics Simulation

• Simulation and Collision Detection for various shapes

  • Sphere
  • Oriented Box
  • Capsule
  • Cylinder
  • Convex Mesh
  • Triangle Mesh
  • Height Field

• Collision detection

  • Raycast Test
  • Overlap Test
  • Sweep Test
  • Bounding Volume Hierarchy
  • Sweep and Prune
  • Gilbert–Johnson–Keerthi algorithm
  • Expanding Polytope algorithm

• Numerical Method

  • Symplectic Euler / Implicit Euler / Verlet Integrator
  • Jacobian Matrix
  • Sequential Impulse Solver
  • Global LCP Solver using Projected Gauss-Seidel

Position Based Dynamics

Fluid Dynamics Solver

Vehicle Dynamics / Autonomous Driving Simulation