Half-Life Mapping Resources
This is my Half-Life one mapping resources section. If you're interested in mapping for the source engine simply check out the Source SDK on Steam. Here you can find direct downloads* or links to all the tools you need to map for Half-Life and some that are just useful.
Valve Hammer Editor
Download VHE v3.4
Download VHE v3.5b (requires v3.4)
The editor, both versions 3.4 and 3.5 beta. The beta has unfinished features and seeing as it's been that way for over two years it is likely to remain that way, however it does have the useful ability to display models in the editor unlike 3.4.
(If you're having trouble displaying models in the editor try here).
Zoners Half-Life Tools
These tools convert your .map / .rmf into a working .bsp file for Half-Life. There are a couple of other builds of these tools, for example XP Cageys version developed and used frequently within the old Natural-Selection Community, however I've been unable to find a maintained version of these tools so instead am linking to the 'vanilla' - maintained - tools which will see you along fine unless you have an inordinate amount of horrendously complex brushwork and lighting.
Nemesis' tools
Nemesis has made many extremely useful tools for both Half-Life and Half-Life 2 development, especially mapping, which can been found at his website:
http://nemesis.thewavelength.net/
Microsoft .NET framework is required for his tools to work, he has the latest required version clearly linked on his website. Below is the blurb for two of his tools to wet your appetite.
About GCFScape:
GCFScape is an explorer like utility that enables users to browse Half-Life packages and extract their contents. GCFScape supports .bsp, .gcf, .ncf, .pak, .wad and .xzp packages and runs independently of Steam.
About Crafty:
Crafty is a 3D object, material, model and file browsing utility targeted towards Half-Life modders or enthusiasts looking for a Steam Independent application for quick previews. It currently supports Half-Life 2 .bsp, .mdl, .vmf and .gl formats along with Half-Life .bsp, .mdl, .map and .rmf formats in a variety of render modes.
Wally
http://www.telefragged.com/wally/
This lightweight program allows you to view, edit and create wad texture files (one .wad contains many textures in case you didn't know) and explore the .pak files included in half-life, although if you have Half-Life on Steam you'll also need GCFScape to get the .pak files from the .gcf files.
Half-Life Model Viewer v1.3
Download Half-Life Model Veiwer v1.3
This allows you to preview model files which is useful when you're looking through reems of .mdls trying to find one suitable for your needs, it's a lot easier than inserting them one by one into the editor!
Sprite View
This allows you to see and edit sprite files for half-life, a useful litte tool in the same way as the Model Viewer.
Winextract
This very useful tools allows you to extract the .wad texture files that are encoded in .bsp files, very useful if you lose your custom .wads but still have your .bsp files. Can also be used extract textures from someone elses map but remember you need to ask the author of the textures for permission to use them in your own map!
Winbspc v1.2
This allows you to turn bsp files into map files you can view in the editor, this is great for finding out just how people have managed to do things, but you should not attempt to modify and re-release any other mappers work. If the distastful nature of act of 'ripping' isn't enough to disaude you it will be extremely difficult anyway, because the conversion is far from perfect, much more suitable for observing entity set ups than stealing brushwork.
Useful Links
This list of links used to be a lot longer, however Half-Life is now a very old game, the community is much reduced and less and less independant sites remain active, most sites have moved onto Half-Life 2, but some leave their Half-Life sections up.
*None of these downloads are my work, there are copyright of their respective authors and I claim no credit for them. I also am not responsable for any damage caused to your computer if you install these programs and they go wrong, and neither are the authors probably, check their disclaimer.