**Euler integration method**, i.e.

position += velocity * dt; velocity += acceleration * dt;I have used this simple approach for a very long time myself. Recently I stumbled across an article saying that the

**Euler integration method sucks**and an integration method called

**4th order Runge-Kutta (aka RK4) integration is much better**for non-trivial games. I was interested in the difference in accurucy of these two methods so I have worked on an application to show the difference. It is written in C#/Managed DirectX and is a simple app with the only purpose of integrating particles positions and velocities when affected by forces from attractor masses. The test app can be downloaded from the Downloads section of my site. Features:

- GPL:ed source
- Clean source code
- Well commented code, easy to follow and modify
- Modular design, generic RK4 implementation

**Known bugs:**Even though we use the RK4 integration, particles still "explode" when they come too close to an attractor. This is due to the fact that the particles have an acceleration of about 100000000 pixels per second

^{2}very close to the attractors. (1/distance

^{2}, remember?). Hopefully, this application will spread the usefulness of RK4 to game programmers.

**References:**Gaffer's articles on physics programming in games Mathematical version of RK4 If anyone have any questions or comments regarding the source or app, feel free to ask! [Edited by - Enselic on March 12, 2006 4:50:06 AM]