So just how do you make rain? All will be explained in this tutorial.

Create a brush with the “nodraw” texture covering the area you want the rain to appear in your map.

Example:

See Screenshot A and B


With the brush selected right click it in the 2d view and then left click on “Tie to Entity” or with the brush selected just hit “Ctrl+T”.
Once you have done this a properties box should pop up.
Go to the “Class” menu located in the top left, click on the arrow and scroll down until you find “func_precipitation” click on it, then click on apply in the bottom left of the “Object Properties” box.

Example:

See Screenshot C and D



Congratulations you have just created rain, compile your map and check it out.




Now you have rain in your map how about customising it so it fits in with your maps atmosphere? I’ll explain the rains properties below.

Name = the name that other entities refer to this entity by.
Just type in the name you would like to give to the entity and hit the “apply” button located in the bottom left. Remember entity names cannot have spaces in.

Parent = the name of this entity's parent in the movement hierarchy. Entities with parents move with their parent.
To connect this entity with a parent entity just scroll down the menu till you find the name of the entity you would like to tie your rain entity to.

Density = this setting determines how hard you want it to rain, the setting ranges from 1-100%.


1% is a light shower.
100 is a heavy down pour.


Colour = this setting is used to define the colour of your rain. Just hit the pick colour button and choose one you like.

Precipitation type = this setting is used to define what your rain looks looks like in game.
If you want to give it the look of snow, select snow from the pop down menu.
If you want to make it look like rain, select rain from the drop down menu.

To view the object properties box, just select the entity/brush, right click and scroll down to properties.

And there you have it ladies and gents. That’s all there is to know about rain, hope this has helped, happy mapping.