www.Play With Cheats.com

Codes for Demo Version

First off, start a server with cheats enabled using the devmap command in the console. Ex. "devmap q3test1" Once in the game, go back in the console and type any of the following:

god God Mode
give all Get All Weapons & Grappling Hook
give health Get Health
give armor Get Armor
give quad damage Get Quad Damage
give personal teleporter Get Personal Teleporter
give gauntlet Get Gauntlet
give machinegun Get Machinegun
give shotgun Get Shotgun
give granade launcher Get Granade Launcher
give rocket launcher Get Rocket Launcher
give lightning gun Get Lightning Gun
give railgun Get Railgun
give plasma gun Get Plasma Gun
give bfg10k Get BFG10K
give grappling hook Get Grappling Hook
give ammo Get Ammo

Unlock All Cinematics

From a dos prompt in your Quake3 directory, type:
quake3.exe +seta g_spVideos " ier11 ier22 ier33 ier44 ier55 ier66 ier77 ier88"

Unlock All Levels at Skill 1

Bring down console and type: /iamacheater

Unlock All Levels at Skill 100

Bring down console and type: /iamamonkey

In order to use the following cheats in multiplayer mode, the server must have cheats enabled (ie: /devmap +map [name])

God Mode

Bring down console and type: /god

All Weapons

Bring down console and type: /give all

You can also use the following codes with the /give command:

health
armor
ammo
personal teleporter
quad damage

Cheat Codes

A few select commands are considered "cheats", and can only be activated under certain conditions. To activate cheats, type:

/sv_cheats 1
from the console. From there, load any map using the /devmap command. For instance:

/devmap q3dm15
will load "Demon Keep" with cheats enabled. You can only use cheats when using the "/devmap" command -- using the standard "/map" command will not allow cheats.
Once you've got cheats enabled, some other useful commands:

/god - "God" mode. You are invincible and cannot be hurt by weapons.

/noclip - "no clip" mode. You can fly through walls and floors, and basically go anywhere you want in the level. (Great for taking screenshots.)

Console Commands

There are a LOT of commands and variable you can play with in Quake III. These only begin to scratch the surface, but are some of the more useful and interesting ones. Keep in mind that some of these can only be used while in "cheat" mode, and other settings may be locked on certain servers, in the interest of keeping al players equal.
If you want to see the complete lists:
/cmdlist - will produce a list of commands
/cvarlist - will produce a list of console variables
You can also output this to a text file by typing

/condump filename.txt
This will output the contents of the console to a text file in the Quake3/baseq3 directory.

/reconnect
Will reconnect you to the last server you were connected to. Useful if Q3 dumps you to the main menu during a map change for no apparent reason.

/bindlist
Will produce a list of all currently bound commands.

/bind
One of the most basic commands, this will "bind", or assign a command to a particular key.
Usage: /bind " "
Example: /bind space "+zoom"

/say
Will produce a chat message onscreen. Used with the /bind command, this is an easy way to set up chat messages.
Example: bind F5 say "ouch! that hurt!"
Do NOT abuse this command. Spamming servers with lots of useless chat is an easy way to get kicked off a server.

/say_team
Allows you to send private messages to your teammates. VERY useful for Capture the Flag matches.
Example: bind I say_team "Defense: Incoming Enemy!"

/messagemode 2
Bind this command to a key to enter "team chat" mode. Anything you type after this command will only be sent to your teammates.

/kill
Will cause you to commit suicide. A handy way to lose a frag.

/callvote [proposed vote]
This command can be used to propose changes on a server, and allow all the players on the server to vote on it. This can be used to change maps, game modes, settings, and even kick players if necessary. To vote on a proposed change, press F1 to vote "yes" and F2 to vote "no".

Examples:
callvote map q3dm9
callvote g_gravity
100 callvote kick sluggo

/quit
Quits the game.

Viewing Options

/cg_draw2d (deafult: 1)
Will turn your HUD on and off (0=off, 1=on)

/cg_fov (default: 90)
Will alter your on-screen field of vision. Lower settings are more zoomed in; higher #'s give you a wider view, but can get skewed at anything above.

/cg_zoom fov (default: 22.5)
Will alter your FOV when in "zoom" mode.

/cg_drawFPS (deafult: 0)
Will display your framerate in the upper right of the screen. (0=off, 1=on)

/cg_drawGun (deafult: 0)
Will toggle your gun model on and off the screen. (0=off, 1=on)

/cg_drawTimer (default: 0)
Will display elapsed game time in the upper right of the screen. (0=off, 1=on)

/cg_gibs (default: 1)
This activates the splatter that is so much a part of shooters these days. Setting to "0" can help keep things clean in heavily trafficked games. (0=off, 1=on)

/cg_simpleItems (default: 0)
Will turn all items into 2D sprites. Can help improve performance on slower systems. (0=off, 1=on)

/cg_drawTeamOverlay (default: 0) Will toggle the very useful "team overlay" on your HUD, which will allow you to see the health, armor, and current selected weapon of all your teammates. (0=off, 1=on)

/cg_thirdPerson (0/1; default: 0)
/cg_thirdPersonAngle (0-360; default: 0)
/cg_thirdPersonRange (default: 40)

These three commands will allow you to play with Quake III's "third-person" view. Setting /cg_thirdPerson to 1 will activate the view, and /cg_thirdPersonRange will set how far behind you view your player from. /cg_thirdPersonAngle will rotate the camera around your player; set the angle to 180 and you'll get a good head-on look at your model.

Useful Server Commands

These are some useful commands you might want to use when running a server. Some of the variables require the map be restarted before taking effect; use the "/map_restart" command to accomplish this.

/serverinfo
Will produce a list of current server settings.

/map
Will load any map with your current server settings.

/map_restart
Will reload current map. You may have to use this command before various server settings can take effect.

/sv_hostname
Change or view the current server name with this command.

/g_gametype
Will display or set the current game type:
"0" - free-for-all DM
"1" - Tournament 1-on-1
"2" - Single-Player
"3" - Team Deathmatch
"4" - Capture the Flag.
Example: /g_gametype "3"

/sv_maxclients
Will display or set the maximum # of players on a
Example: /sv_maxclients "10"

/timelimit
Displays or sets the server time limit.

/fraglimit
Displays or sets the server frag limit.

/bot_minplayers
This command can be used to keep a server populated with random bots when empty. Bots are kicked when players join. Example: /bot_minplayers "4"

/addbot
Can be used to manaully add bots to a game.

/kick
Will kick any specified player from the game.

/g_gravity (default: 800)
Set or display the world gravity with this variable. (Lower number is less gravity.)

/g_speed (default: 320)
Set or display player running speed with this variable. Setting to 1000 will produce highly interesting results.