This function can be used in many different ways some of which are helicopter blades, spinning doors, spinning floors, and fans.

I like this function because it can add a lot to the environment of your map. When used as a fan in conjunction with trigger_push, you can blow a person off a platform or such them into the sharp blades which is what we are going to create here.

The entities that will be used are:

func_rotating
trigger_push

1. Take some time creating the fan blade to your liking. I will often create 2 separate brushes, then move their edges to create opposing trapaziods for each blade as in the sample map provided for this tutorial.

2. o­nce the fan is created, placed in it's final destination and ready to, deselect everything and select the origin texture for our next brush.

Create a brush that will be used as the axis for the fan to spin o­n. Be sure to place it exactly in the center of the fan (unless you want the fan to wobble).

3. Select all of the brushes that you wish to have spinning with the fan including the origin brush and turn them into a func_rotating.

Open the entity editor and select the appropriate axis you want the fan to spin o­n.

Select the flags for start_on and give it a dmg of about 100. The dmg is the amount of damage inflicted when the player touches it. A setting of 100 should kill them slowly enough for them to know what is happening, yet quickly enough that they won't have time to figure a way out.

Set the speed to a high number like 8000. The default speed is quite slow.

This is the end of the fan construction. Now we will add the push, or the wind, that will suck the player into their death.

4. Create a block, using the trigger texture, that fills the area you wish to grab and suck the player into and through. Make the block o­nly large enough to grab the player (about 8 units high and wide) but still the full length of push into the fan. Making the brush too large will just cause the player to get sucked in sooner than you would have expected.

5. Open the texture editor and check the content flag for mist. This will allow the player pass through the brush and avoid getting stuck.

6. Turn this block into a trigger_push and open the entity editor.

Give it angle that heads into the fan.

Set the speed to your liking. I prefer to choose a speed of about 30 to taunt the player and make him think that their is possible escape.

And you're all set to run.