Rune's Particle System

Rune's Particle System is an include file package for use with POV-Ray 3.5. Water, smoke, fire and sparks are just some of the things it can simulate. With a generic and non-specialized engine, the system makes it easy to customize the simulation to a wide range of uses. The package comes complete with include files, documentation, and several sample scene files that makes it easy to get started.

The documentation is included in the zip file, but you can also see it here.

Features

The system does not use very advanced algorithms. It doesn't support particle-to-particle interaction, so things like water and smoke can only be simulated with limited realism, because the system has no fluid dynamics. Still, in some cases the system produces very nice results. The real strength though is that this system is very user-friendly and easy to use compared to many other particle systems I've seen.

Feature highlights:

• The look of the particles can be completely customized by the user.
• Several predefined types of particles in separate include files.
• Support for collision detection against any object.
• Upon collisions the particles can bounce or float along the surface, depending on the settings used.
• Support for object emitters of any solid object.
• Death objects can be specified that kill particles upon collision.
• Gravity and wind can be defined for every point in space and can change over time.
• The number of calculation steps is independent on the number of frames.
• Support for looping animations.

The particle system is a project I made for fun. I've been working on and off on it since February 2001, and now in October 2002 it's finally finished. Many thanks to the beta testers who in the later stages helped me to test the system for bugs, and by coming with suggestions for improvement.

Fountain demo scene

This is an attempt at a somewhat realistic scene with a fountain of water. The particles are thrusted upwards and then fall down. The water at the bottom is not part of the particle system though. This scene also demonstrates the faked motion blur of the water drops. They are simply scaled longer in the direction of movement.

Magic Lamp demo scene

Here a lamp object is used as an object emitter, so that particles are emitted from the surface of the object. The particles here are small lens flares. This animation also demonstrates transferring of kinetic energy, where the particles inherit some of the movement from the object they are emitted from.

Flow demo scene

In the particle system, the collision settings can be set so that particles flow along the surface they hit. This can be used to create some nice flowing water, like in this animation.

Camp Fire demo scene

The particle system can also be used to make some nice fire effects, where each particle acts as one flame. These flames are each made of spheres filled with media.

Smoke Trail demo scene

Smoke is also a good task for a particle system. The smoke in this demo scene is thrusted out backwards from the missile, and is also affected by wind. This demo scene is not very realistic, as I just wanted to show off some effects, like how you can control the color of particles over time if you want.

Hose demo scene

A simple simulation of water, where the particles bounce off the ground. Bouncing is easier to do than flowing, so this was one of the first water-simulations I did.

Magic demo scene

Magic-like star dust effects like this is what originally made me start creating the particle system. The physics here are simple - the particles are only affected by simple gravity. A good start if you want to create a particle system.

Pentagram Fire demo scene

The particle system can also be used to set objects on fire. Here a pentagram symbol is used as an object particle emitter, so that particles are emitted from the entire surface area of the object.

Blow Up demo scene

Four particle systems are used here: One for the initial explosion, one for the steady beam of fire and smoke, one for the dust, and one for the debris. The effect is not completely realistic, as the system has no fluid dynamics to control how the smoke behaves, but this is as good as it gets with this system.

Inner workings

The core of the particle systems is the arrays with the data for each particle. To simulate the movement of the particles, the same calculations are done over and over again. In each calculation step the following happens:

• Each particle is moved by it's current velocity (current location minus last location) plus gravity (for example -y). More forces can be added if necessary. The life is also decreased by an amount. Furthermore things like collision detection are also calculated here.
  
  
• In each calculation-step some particles die (Life goes below 0). When this happens the life is set to -1 so the system can recognize that the element is "empty".
  
  
• In each calculation step new particles are also created (they are created in "empty" elements). Their initial "last" location is set equal to the current position of the emitter-point. Their initial "current" location is the same as the "last", but with some randomness added. The life of the particle is also initialized.

For each frame in the animation a number of calculation steps are done. After the last step for a given frame, the particles are placed in the scene according to the latest calculated locations, and after that, file I/O is used to save the data in a file to make it available to the next frame in the animation.

That's just the basics. It would take forever for me to explain it all in details. For general information about particle systems, I suggest that you have a look at Hugo Elias' page about the subject. You can also look at the source code of my system to see how it works, and you can also mail me if you have any specific questions.