Resources: Valve’s API

I continue with the list of the pages I used the most on Valve’s Developer Community, or also called Valve’s API. There are in fact two lists: pages about mapping, and those about modding.



  • Ending a Portal map: a small tutorial about ending maps like Portal’s bonus maps.
  • Hammer Hotkey Reference: the complete list of all the shortcuts on Valve’s Hammer Editor.
  • 3D Skybox: an explanation of what they are, what is their purpose, how to do them (though I recommend following the tutorial I gave in this article).
  • Sky list: a list of all the different skybox textures, organized by Source games and mods.
  • Filter Applications: filters are a good way to authorize or forbid actions or events in a map. For example, I used some filter_activator_class in the map “Open Ground Park” to trigger the trashcans into recognizing the cans.
  • Filter_activator_class: a filter that will only allow (or forbid, depending on how you configure it) objects or entities from the specified class.
  • logic_case, logic_timer, math_counter: those are entities I tried to use to make a custom chronometer. I failed, but you can still try to do it, or try inventing something else: these tools are powerful.



  • Mod wizard complete: that’s the first page you get after successfully installing the mod wizard. It gives starting pages to create your own mod.
  • Category: Modding: this is an organized page around modding. Modding implies several domains: Advice, Getting started, Releasing, Source’s features, Modifying the menu interface, General scripting, and of course the Community.
  • Gameinfo.txt: it’s maybe the most important file when starting modding, because it tells the game engine where textures have to be picked in order to use them in-game. The tutorial about fixing HL mods on SteamPipe is directly linked to that file.
  • Non-code mod settings: the files listed here are those I modified the most, with those of the following link. You don’t need any programming skills in C++ to modify or to understand them. These files can change the interface, its items displayed, its panels, etc. They do not change the behaviour of the game itself.
  • Adding chapters to your mod: Having 32 chapters in my mod, I used quite a lot this page. It explains all the different steps you have to follow to add a chapter to your mod. Beware, the maximum number of chapters displayed in the “new game” menu is 32, unless you know where that parameter is defined (which I don’t, alas).

Resources: Tutorials

Finally, I will list here and in the following “Resources” articles all the resources I used: tutorials, ideas, specific pages on Valve API, solutions to bugs and errors. It took me hours to gather this information, so the aim of these articles is to ease future modders research.


  • Half-Life 2 Map Editing Optimization Guide: this is the most complete optimization guide I found, made by the most active community of mappers and modders : (description in the article “Sources”).
  • Advanced Leaks Guide: a tutorial explaining what is a leak and the best way to avoid them, or to find them.
  • Re-scalling models: I finally didn’t use it, but I found it interesting as the method is not that easy. Valve’s Hammer Editor does not allow to re-scale models, and this is a very good way to do it.
  • Stairs: a nice tutorial explaining how to make stairs while optimizing nodraw areas, and using the least textures possible.
  • Digital Countdown Timer Tutorial: I finally didn’t use it either, and the method is quite difficult. I wanted to have a chronometer ingame, but it seems to be far more complicated than I thought.
  • Making a cool 3D Skybox: skyboxes are a way to virtually expand the size of your map while saving on compiling time, but they aren’t that easy to make. This tutorial, even if it was made for Team Fortress 2, is very useful as the Source Engine is used in both cases.
  • Une map pour le moteur Source avec Hammer 4 [A map for the Source Engine with Hammer 4]: maybe the only French resource, yet a nice tutorial on the basics of map creation through Valve’s Hammer Editor.
  • Fixing Half-Life 2 Mods on SteamPipe: when Valve changed their method of packing materiels and models, they changed also how mods were managed by their games, and everything broke up. This tutorial tells you how to do and what to do to have your mod working well.
  • How to make TF2-doors in Valve’s Hammer Editor: a quick tutorial, again for TF2, but working well for HL2.
  • Complete guide for customizing a single-player mod: this tutorial is now as complete as its title assures it, but it can solve several problems you may meet. Images are no longer available.


Here I will only put the general sources I used. All the precise and detailed pages will be in the “Resources” article.

  • is a website about Half-Life news and tutorials.
  • TF2MAPS is a website about maps for Team Fortress 2, which is also built with the Source Engine.
  • Steam Tool Discussions Forum on Stean User’s Forums is a forum dedicated to Source creation. It can be about materials, models, maps, C++ coding, and whatever related to Source SDK.
  • Valve Developer Community is a kind of Valve API. There are tutorials, details about Hammer Editor and its content, tips and tricks to help developers, etc.


To create this mod and its content, I used several tools, sources and resources. This article is the first in a serie which aim is to compile and unite these sources, to help modders in finding information.

This article will just list the tools I used, for what and where they can be found / downloaded.

  • Microsoft Visual Studio 2013 (Professional Version): due to the fact that I’m a student, I got a free and legal copy of the software. See Microsoft DreamSpark for more information. I used this software to modify a VS project file, in order to create and then compile the mod.
  • Valve’s Hammer Editor: it’s a free software, published by Valve, who also created the game “Half-Life 2”, which I am also using as a game basis. The Valve’s Hammer Editor is free to use, if you have a Steam account (which is free to create), and at least one of the game using the Source engine (if you want to mod for HL2, you have to possess it).
  • One of the many targa converter: .tga is a file format used by Valve. More information here.
  • VTFEdit: it’s a free tool used to create and convert VTF and VMT files, created by a modder (Nem). You can find his website here. He also created several tools to ease modders work, as the Terrain Generator.
  • IcoFX: it’s a paid (with time-limited free version) icon creation software. I used it to create the icon of the game, in a better way than using Paint.
  • Error Fixer: a useful tool for mappers, to detect what’s wrong in the compile log of the Hammer Editor, and it provides also a bunch of solutions.