tools:

level editing and mod utilities

this list is intended for those new to modding game engines and editing game data.
in the future this tools section will include lists of tools for a variety of game based development projects, inlcuding engines currently being developed at selectparks. in the meantime we have included free tools for editing and modding for the Quake [ I, II, II ] Half-Life andUnreal engines.
while many more tools are available than listed here, these will cover most requirements when working with these engines.
of course many other engines SDK's and tools exist, however the tools resourced here are used by large communities of developers, modders and editors, so support is always nearby.

audio editors:

snd
an excellent sound editor for linux

audacity
an excellent sound editor for Windows, Linux and the MacOS

cool edit 2000
a good shareware sound editor for windows

terrain editor

terragen
the best game friendly terrain editor available

level editors:

mario improvement 3
freeware super mario brothers 3 editor

quakeII based engine tools:

MilkShape3D
An excellent modeller that currently supports 37 different file formats from 27 different games/ engines/programs.

PakScape
for exploring your pak files which contain a majority of the game data / art

Wally
a basic image editor and texture library maker for a variety of quake based games

Quark
a multipurpose tool for quake-engine based games

Tread3D
user friendly level editor

Smdlexp.dls
exporter for 3DMax 3.1

Half-Life

Zoner's Half-Life Tools
compile tools to make half-life BSP's

MDL Viewer
a tool for previewing models used in Half-Liie games.

worldcraft3.3
level editor for half-life.

Quake III

modmaker
a tool to keep track of work when making mods for the QIII engine

Q3Radiant + Compile tools
editor and compile tools for QIII

GTKradiant
an excellent level editor for Quake III

Quark
a multipurpose tool for quake-engine based games

Quake III engine source code