I thought I would do a tutorial for a bunch of very simple entities that some people might not know what they do.
trigger_push
The trigger_push is the same as it was in Quake1. Use it to push the player in a given direction. (wind tunnels, etc)
There are two key/value pairs, and one spawnflag for the trigger_push:
angle
use this to determine what direction the player will be pushed. 0-359 on the xy plane, -1 for up, -2 for down.
speed
This key/value pair determines how fast the trigger will push. The higher the number, the faster (and farther) you go.
PUSH_ONCE
Set this spawnflag if you only want the trigger_push to work once, and then remove itself.
First thing we need to do is define the area that will be pushing. Make a brush where you want there to be a push, and make it a trigger_push. (note: this brush won't be visible in the game.) Set the "angle" key to the direction you want it to blow the player. That's it.
Note: the trigger_push is not triggerable. This means you can't trigger it to push only at certain times. You can use the PUSH_ONCE spawnflag to remove it, but you can't start it off, and then turn it on, or turn it back on once it's removed.
trigger_hurt
The trigger_hurt is another pretty easy entity to use. It defines an area that will inflict damage on the player. Trigger_hurt can also be used for setting traps..like the floor opens and the player falls into a pit of spikes. Just draw a brush covering the tips of the spikes and make it into a trigger_hurt.
Here's the key/value pairs and spawnflags:
dmg
This is the amount of damage caused each server frame.
SILENT
Setting this spawnflag makes it...well...silent
TOGGLE
Spawnflag used for a trigger_hurt that is fired by another event. Toggles it on and off each firing.
START_OFF
Also used for a triggered trigger_hurt. Starts off.
NO_PROTECTION
Causes damage regardless of godmode or invincibility powerup
SLOW
Causes damage at a slower rate
All you need to do to make a trigger_hurt is make a brush, and make it into a trigger_hurt. You can then set the spawnflags according to your specific needs.
The trigger_hurt is triggerable (is that a word? If not, it is now,) so you could have an area where the player wasn't taking damage but then one of their actions triggers something that causes the player to take constant damage until he/she is out of the area of the trigger_hurt. There are a lot of uses for this.
misc_banner
This is the cool wavy flag that is seen on base1. Pretty cool looking. It's uhhhh...very easy. Just place it where ever you want and thats where the flag will appear. Angle determines which side of the flag faces what. In the docs it says it is 128 units high but it seems much bigger to me.
target_help
This is the entity that makes those messages appear on your computer. It also makes the computer blink. They used it in quake2 to tell you about your primary and secondary missions on each level.
key/value pairs and spawnflags:
message
This is the actual text that will appear in the help computer. The maximum characters allowed is 32. Any more than this, and you will get a "com_sprintf: overflow of <whatever> in 32" error. if you need to break up a line, use \n.
HELP1
Set this spawnflag if you would like the text in the "message" key to appear as a primary objective. If this is not set, the message will appear as a secondary objective.
First thing you want to do is create whatever action is going to fire the target_help. This can be any event that can fire another event, Including (but not limited to) trigger_once, trigger_always, killing a monster, opening a func_door, pressing a func_button, etc.. In this case, we'll use a trigger_once. (If you're a bit fuzzy on triggers, check the tutorial on the trigger_ entities.) Place the trigger_once where you want the computer to be updated. You may want to have it stretch across an entire room, just to make sure the player will pass through it. Now give it a key of "target" with a value of "helpme".
Now, we'll set up our target_help. In this case, we'll want it to say something stupid, like "Make stuff die", and we want that to be the primary objective. (This is a tutorial, we don't need a subplot, dammit.) First, though, we need to tie it to the trigger, so give it a key of "targetname" with the value "helpme". Now, the objective. Give it a key of "message" with the value "Make stuff die" (remember, don't use quotes in message values, or you'll get "line is incomplete" errors when you try to compile). Now, all we have to do is set the "HELP1" spawnflag, to make it a primary objective, and you're done.
I have put examples of all these entities on the example map (rust8.map). So if you are having any problems then be sure to check it out. Any other questions please post to the discussion board.