"Rain in Half-Life?"
Yes! You've been all dreaming of it!

This tutorial file explains how you can easily add rain in your levels.
You'd better use Valve's Worldcraft

What you need:
* Nothing else but the rain.spr sprite file!

The rain effect could be done with a 3D model or with a C script to make it better (random placement,...), but it would need new .dlls and wouldn't work in single player.

What I bring to you is a really easy way to add a cool special fx in your single and DM levels.

1st step:
Place the RAIN.SPR file in your valve\sprites directory.

2nd step:
In your level you need 3 entities for each drip (so copy/paste these entilies in the area you want the rain to fall, and space them, more or less, depending the rain intensity):
- place one "env_beam" entity anywhere in your level.
- and two "info_target", one for the start of the water drip and the other for where it ends (call them s1/e1, s2/e2,... or something like that). You may place them on the same vertical line if you want the rain to fall straight to the ground. But if you want to add a wind effect, move all the end entities several units away from the start entity in the top view of you editor.

3rd Step:
- In the "env_beam", you need now to specify the "Start Entity" (put s#) and the "Ending Entity" (e#).
- Set the "Life" to 0.
- Set the "Width of beam" between 16 and 32 (regarding how phat you want the drip to be).
- Then in the "Sprite Name" section, enter "sprites/rain.spr".
- Set the "texture scroll" to about -20 for a fast rain (You can slow down the rain or accelerate it but you always need a negative number).
- To improve the rain quality in the "Flags" enable the "Start On" and "Shade Start" flags (the rain will shade on its top border).

Tips:
As you can see in the sample level, rain is much better in outside places :).
In order to improve the rain feeling don't choose a hot sun-burned desert sky. You can specify which sky to use in the "Map properties". You may want a cloody sky so use "dusk" (the one in my level) or "night" or a strange alien sky.
You'd get a better effect if you use a "env_light" with a gray-blue light quiet dark.
Use also a "func_water" on a non-flat soil as in the sample level (it looks so cool in software!).
And at last put in the middle of you rain zone a "ambiante_generic" using "ambience\*waterfall3.wav" (a cool rain sound from the valve pak).

Have a look on the the sample map (rain.bsp)

Feel free to e-mail me if you have some issues. You can also modify the sprite, change it (blood rain, snow or whatever). And try everything you want with the "env_beam" to improve the rain fx.

Mail me: Freon (Fabien Cortina)