One of the large (and largly unknown) benefits of being on the Orange Box Engine as a Source mod means that we have access to Valve's nifty particle editor. This allows us to create particles ranging from something as simple as a puff of smoke coming from a gun muzzle to a several-thousand particle rain shower with water impacts and ripples. Particles really help to add movement and life to an otherwise static map. Let's take a look at some of the particles of Beta 4, with images and brief, simple explanations:
Runway Snow Drifts
http://img194.imageshack.us/img194/3441/gerunway0003.jpg
Puffs of snow which float across the runway, similar to what you would see if you were to drive around when it's snowing. The particle works by faing in particles at random offset points along a certain line, then they float sideways and fade out.
Basement Ceiling Leak
http://img18.imageshack.us/img18/7879/gebasement0006.jpg
A particle I put into basement to explain why the bottom area is flooded, and adds movement to the otherwise dark and boring area. It has a starting point with a rapidly animating water particle, and then more particles are shot out at random angles and pulled down by gravity.
Caves Rain with Ripples
http://img109.imageshack.us/img109/7898/gecaves0004.jpg
This is basically a bunch of stretched white particles spawning in three different locations, then being randomly offset and being pulled down. Then, down at the water, there are a bunch of randomly placed expanding/fading ripple effects.
Rolling Explosions
http://img41.imageshack.us/img41/4168/gebasement0007.jpg
Everyone's favorite, this is actually several small animated fire sprites with a single large fire sprite behind them, with flecks of shit flying out and bouncing all over the place, as well as smoke that hangs around after and little env_steam entities are spawned above it as heat waves that rise from the inferno.
Hopefully all of you enjoy the new effects, its certainly been a fun experience for me to learn the editor over the past year.