Not Only, But Also: Source SDK To Be Free

Source is one of those words that seems as if it's spelt wrong the more you look at it. Source. Source. Source.
Here’s something: since the release of Valve’s free Source-based co-op shooter Alien Swarm which took us all by surprise last year, hippies and socialists have been able to get their hands on a Source-based game without paying a thing, which in turn lets them play those lovely Source mods for free as well. Well, we’ve just received word from Valve’s Robin Walker that due to the recent release of a free Team Fortress 2, the Source SDK will soon become free to use in its entirety, for everyone.

The Source Software Development Kit, for those of you who’ve never clicked the Tools tab in Steam, contains everything you’d need to make a mod, except for personal ambition. It has everything from the infamous Valve Hammer Editor to Face Posers and Model Viewers. At the moment, to gain access to the Source SDK you have to purchase a Source based game such as Half Life 2, or as the official website states, Team Fortress 2. Which is of course now free.

News came via this Reddit thread detailing the exploits of an enterprising young man going by the name of Riley, who just happens to be the playtest leader of esteemed Source mods Zombie Panic Source and No More Room In Hell. They asked Team Fortress 2 developer Robin Walker if buying an item in the TF2 Mann Co. Store would give access to the Source SDK, Walker had this to say:

Yep. That said, your email has triggered a process here that made us re-examine that, and we’re going to just go ahead and make the Source SDK freely available. Thanks for making us better!

We emailed Walker for further confirmation, and he went on to explain:

We are in the process of getting it all done. It’s a bit messy because we have multiple versions of the SDK, and there’s some dependencies we need to shake out. But yes, the gist of it is that we’re just going to go ahead and make the Source SDK freely available.

Isn’t that nice. Makes me wonder if everything Valve makes from now on will be free OF COURSE THEY WON’T DON’T BE SILLY. We’ll probably be seeing an official announcement soon (and an update to that official page), but in the meantime you might want to brush up on your Hammer skills by having a look at the official SDK Documentation.

What are your favourite Source mods, readers?


  1. Antlia says:

    Zombie master was good.

    • treat says:

      I agree with this statement without irony or sarcasm.

    • Broadsword says:

      Zombie Master was my favorite source mod ever! Hidden is a close second. Just goes to show that production values are not always needed for a good time.

      Also calling NMRiH esteemed is pretty funny. After a history of bad PR and a reputation as vaporware it has become a sort of joke among zombie mod fans. Of course its development has recently picked up again and it’s looking like it may finally form into something good.

    • Mendrake says:

      Yup, zombie master ranks up there as one of my favorite games of all time. It was kinda buggy, it was kinda unbalanced, but it was a simply amazing game. If only it still existed, if only someone would ressurect it from the dead. I would play it, and I am sure if it was brought back most of its old fanbase would come back too.

    • ceilingcat says:

      Just to reply to what Mendrake said:
      The original Zombie Master team released their source code 2 years ago and different groups picked up on it to create spin-offs, me being one of those teams.
      (Not going to post the link here, because I do not want to be a filthy spammer).

  2. Bodminzer says:

    This fucking rules. I was just about to start learning the Unreal SDK too. I’m presuming this is nice and easy to use too, judging by the quantity of mods for Source.

    • ResonanceCascade says:

      I’d honestly recommend UDK for the time being. HOWEVER, Valve has said that their primary focus at this time is on tools, so hopefully Source SDK will be pretty kickass in the near future.

      But hey, since they’re both free I guess it wouldn’t hurt to dick around with both and decide for yourself.

    • Bodminzer says:

      I was scared of UDK because I don’t know anything about coding. I just want to be able to make some maps and have all the terrifying numberfucks going on behind the scenes.

    • Bhazor says:

      If you just want to tinker with maps then the Far Cry 2 and Crysis editors might be worth a look.

    • DuckSauce says:

      Ah wrong assumption I shall say as someone who used to be very involved in the mod making scene.
      Still, it was better than starting for scratch and probably better than what used to be available in the past, but UDK by far surpasses it nowadays in my opinion, much easier to work with and much more up to date tools, updates aren’t forced down your throat and it’s much easier to update too(code/script wise, unless you do naughty things…)

      But hey, if you think that, go burn your fingers, maybe if you’re lucky valve pushes out a grand update that prevents that, but I doubt that.

    • Petethegoat says:

      Nice and easy to use this is not. No sir.
      Really, UDK has a lovely pipeline compared to Source. That said, it’s still likely to be worth a look, as you may prefer it for other reasons.

    • Xercies says:

      Eh…no it isn’t. In fact its probably one of the most horrible things to use and I actually model in Maya and other such programs. I really can’t get how people can make any levels in that engine!

    • Theory says:

      That “new tools” quote:

      Gabe Newell: Oh yeah, we’re spending a tremendous amount of time on tools right now. So, our current tools are…very painful, so we probably are spending more time on tools development now than anything else and when we’re ready to ship those I think everybody’s life will get a lot better. It’s just way too hard to develop content right now, both for ourselves and for third parties so we’re going to make enormously easier and simplify that process a lot.

      link to

    • jalf says:

      The Source SDK and tools are abominations, plain and simple. Programming against it is about as fun as sawing your own leg off (only with far more nasty surprises along the way), and Hammer is one of the worst, map editors I’ve ever seen. Unstable, inflexible, unstable and, well, just not good.

      Yes, it is *possible* to make some nice mods, but that’s despite the tools, not because of them.
      I don’t think it’s a coincidence that pretty much every Source game not developed by Valve has sucked.

    • Tei says:

      I am webmaster, so …hu… game developing is not my area. I apreciate and admire mappers, I think creating maps is a 33% of creating games. And It Shows It (read: classic games have classic maps, and forgotten games have forgetable maps)…. but I want to say that probably Hammer is not bad, is just a technology of other era. Probably mappers want to build maps in a different way nowdays (maybe using a full 3D editor?), but you can’t blame hammer for that. Hammer has probably benefict from incremental enhancements. But incremental enhancements are nothing for the people that want a revolution.

      Thats imho, and.. has I say.. this is not my thing.

    • Shodex says:

      Simply put, the Hammer editor is a little harder than making an ice sculpture with a chainsaw.

    • pepper says:

      I grew up with hammer, so I always found it much easier to work with additive CSG stuff instead of unreal’s subtractive methods. Although that really doesnt matter anymore for the unreal engine nowadays.
      Programming wise, well I’ve heard horror story’s of both engines, 2 old colleague’s of mine worked with the unreal engine(the actual source code) and absolutely hated it, but i’ve heard the same of the source engine.

      EDIT: I just realized why I prefer the hammer(or worldcraft for that matteR) approach, I grew up with the old Half-Life 1 modding scene, in those days optimization was something very important(ZHLT tools, null faces, VIS portals, etc). With that old approach you could also bend the performance in the way you wanted it to go. Offcourse we never had any control over either the CSG, VIS, RAD or BSP processes.

    • Bodminzer says:

      Gosh, I didn’t expect to see you here Tei! Did people on SA start being nasty to you? :(

    • Wulf says:

      …Vampire: The Masquerade: Bloodlines sucked?

      Well, technically, yes, I suppose it did with them being vampires and all.

      Bloody technicalities.

    • soldant says:

      Hammer/Worldcraft isn’t THAT hard. Then again I started mapping with sector-based engines and then moved on to making Quale and later HL maps. The problem is that it’s a relic of an earlier period of game development, it makes perfect sense to most of us who were around for the start of mapping in HL or Quake. I can see how it’s frustrating to people who weren’t and are used to 3D modelling apps. In any event though I still wouldn’t recommend Source SDK, I’d go with UDK or Unity. The Source engine is getting on in years despite all the hackjobs to add new features, UDK is a bit more dynamic. They’re both reasonably about the same in terms of difficulty (IMO having used both).

    • Tei says:

      @Bodminzer Is weird that you know me from sa, I only have a few post there. There are cool people in SA, is like a small town.

    • ChampionHyena says:

      This, sadly, is the crux of the problem. This is way cool news, and good on Valve for doing it, but they needed to do it WAY earlier than this. Source SDK is an enormous serrated blade of hurt. UDK, meanwhile is just… cuddly.

    • Text_Fish says:

      UDK may be easier to learn than Source or Unity, but everything made in it has that distasteful ‘hollow 1950s film-set’ feel that all Epic games suffer from.

    • ceilingcat says:

      I would not say that Hammer sucks, it is a well made editor, however certain things about it are aged, like for example no lighting preview (at least not something that works easily) but that is more a problem with the engine not having full dynamic lighting.
      Making a successful mod is simply a matter of creating gameplay that works for a large audience. And for that, Source is as good as CryEngine or UDK. The problem is that most mod teams aim way too high and fail fullfilling those ambitions and fall apart.
      Don’t blame the tools for it.
      Certain parts of the Source pipeline are hard to work with but it is not that bad once you know how it works.

  3. ALJA says:

    I hope this is good news for the vampire bloodlines import to modern source engine project. I really want to play that game again with an updated engine.

    • ResonanceCascade says:

      This release probably won’t affect that, since those guys already have the SDK. But anything that might help them help me play a less broken version of VTMB would be great. The last third of that game in particular is just a mess, even with fan patch version 6,994,554 installed.

      Still a great game though.

    • Nick says:

      Nothing can be done about the last third of the game. Bugs are not its problem =(

    • mkultra says:

      Gah. Bloodlines actually finished and in a newer engine would make the cream flow generously.

  4. Jannakar says:

    Not to be churlish or anything but I really would prefer that they drag Hammer into the 21st Century.

    • skinlo says:

      If they can make Portal 2 out of it, does it need to be??

    • Jim Reaper says:

      @ Jannakar

      But, but, Christopher Lee’s getting on a bit now. Dracula just won’t be the same with grey hair & a beard….

    • Schaulustiger says:

      Hammer. You can’t touch this.

    • Jannakar says:

      You could make Portal 2 with a hex editor but that doesn’t mean you’d want to.

      It’s just everytime I start up Hammer I start to look wistfully at UnrealEd… maybe it’s the subtractive approach which seems more intuitive to me (and that’s purely personal obviously).

      It does fill me with awe that Valve (and many other equally talented mod groups) are able to get so much out of Hammer

    • jalf says:

      If they can make Portal 2 out of it, does it need to be??


    • Nick says:

      Hammer is already back in the 21st century! They did Let Me In for example.


  5. fiddlesticks says:

    As far as Source Mods go, Minerva: Metastasis would be the obvious choice I suppose. Zombe Panic: Source is quite good as well.

    That being said, I have a lot more fond memories of various HL1 mods. They Hunger, ETC II, Poke646, Natural Selection, Edge of Darkness, Azure Sheep, USS Darkstar and about a dozen more. Good times.

    • Big Murray says:

      I’d forgotten about Minerva. That really was the highest quality mod I’ve ever played … I wonder what he’s working on these days, after being hired up …

    • LionsPhil says:

      Poke646 was pretty good.

      As was Scientist Hunt, bweeehehehee. Shame it hardly ever had players. :(

      I believe you list is also lacking “Science and Industry” from the usual “good but overshadowed by TFC/CS” set, but I’m not sure I ever got an actual game of that against humans in.

    • pepper says:

      Remember that single player Vietnam horror mod, or the other multiplayer one(Tour of … I think).

      Or The Trenches. Alas, the latest version was never released. It was quite good(MG’s, gass attacks etc)!

    • Matt says:

      Mission Improbable Parts 1 & 2 are some great single player maps for HL2… made by a former GRIN level designer. Word is Part 3 is supposed to drop sometime late this summer.

    • aethereal says:

      Minerva was rather fantastic.
      As far as favorite mods go, I think I would say Dystopia.
      Lasers, cyberspace, and katanas, oh my!
      Its a brilliantly done class-based cyberpunk FPS (no, it was released prior to TF2)
      Unfortunately it has a bit of a difficulty curve that tends to keep the community rather small.

  6. Bhazor says:

    Well the engine has been long surpassed in the past 7 years but its still a nice gift.

    • skinlo says:

      Wouldn’t really say its been long surpassed, only a little in the last few years. The main problem for me is the level loading, and slightly low resolution textures. Portal 2 looks pretty good imo!

  7. Stellar Duck says:

    Favourite Source mod?

    Dear Esther.

    Source mod I’ve spent most time with:


    • rapchee says:

      <3 insurgency
      i wish dear esther had subtitles … it was bit too difficult for me to decipher the talk and walk around. i didn't get too far in it

    • povu says:

      I believe the upcoming Dear Esther remake/indie game release is going to have subtitles (in various translations too). And of course the remade levels to make them longer and with awesome graphics, re-recorded soundtrack with actual instruments, and more voice acting.
      Coming some time this summer…

      See guys? Source still looks fine :P

  8. skinlo says:

    Awesome news! :)

  9. Leelad says:


  10. Namos says:

    It’s almost as if its… open source. (but not really)

    • Tei says:

      I think technically is open source (since you can read the code and the like) but not free software (has theres a eula that enforce rules).

      FOSS has nothing to do with free as in gratis.

    • Forceflow says:

      @Tei: wrong. They provide the Visual Studio project files for building a mod, but there’s no source available for the Source Engine itself, only compiled binaries.

    • Tei says:

      Well… thats don’t sound different than a open source plugin for a commercial proyect. The part that has readable source code ( .cpp and .hpp files) is open and is source, is open source code.

    • steviesteveo says:

      I’m not sure the definition of open source software is that it’s closed source except for the part you write yourself.

      Not to teach anyone to suck eggs, everything on a computer has readable source code and there’s a fair amount of it here that isn’t available openly.

    • Tei says:

      Trust me, I ham doctor.

    • LionsPhil says:

      You don’t get the source to Source and the rights to modify and redistribute said Source source, therefore Source is not open source.

      Worst freaking engine name? It’s got to be a contender.

    • steviesteveo says:

      It’d be the worst name ever if it was called the Open Source engine.

    • Tei says:

      You may not have the sources for the engine. But you have the sources for something, namelly, the “plugin” thingie that people use to make mods.

      People make mods editing C++ files. These files are “open” on the sense that are human readable. And are source. So can be described as open source files. Is not free software, because there are strings attached, but is open source.

      * waves hand *

    • steviesteveo says:

      Free software often has a lot of strings attached. The Gnu General Public Licence even restricts how you can reuse GPL’d code in your own projects (you have to make your own project FOSS to use any GPL material).

      Treating some human readable files you can edit to change how the program works as making the program open source would mean all programs (not just games) with a human readable configuration file are open source and that’s not the case.

      Open source just means you publish the source code for your program instead of treating the working files you used to compile the binaries as a secret so not having the code for the engine is actually pretty fatal in terms of Source being an open source program.

    • Tei says:

      Most FOSS is distributed without a use license. Only a distribution license. The gpl is a distribution license. C++ files are not some random config files, are source code. Not having the source of the engine is unimportant, we^W I am not talking about the engine, but the means to make plugins (mods) that is this sdk.

    • Wardsky says:

      As the open source definition points out, open source doesn’t just mean access to the source code. Things like the code being freely shareable and usable in derived works matter, too. Maybe the source SDK meets these conditions, I don’t know.

    • steviesteveo says:

      Wardsky: Yeah, I’m really just focusing on the source code being open or closed as the first thing to consider when deciding if a project is open or closed source.

      Tei: The only thing in a source mod that could be open source is the output file itself and that’s only if the person making the mod decides to make it open source (they don’t need to distribute their working files). But that’s a bit like saying that Microsoft Word is open source because you can choose to share the files you made in it. Additionally, C++ isn’t magic, it’s text files that, when compiled into a binary, tell the computer how to work.

  11. Gpig says:

    Ugh, now Source looks like a weird word to me. Weird. weerd. wheird. wheared. wheered. wheerd. wierd.

    • MiniMatt says:

      Like “squirrell”. Or is it “squirrel”? I dunno. They’re both wierd.

  12. Boozebeard says:

    You would think anyone who is serious about making mods and by connection games would own at least one source game already.

    • gwathdring says:

      And thus they aren’t really losing money by giving the engine away to people who would be willing to buy a game just for a crack at the engine. Good customer service AND savy business plan. Valve likes doing that sort of thing.

  13. sockpuppetclock says:

    Way back when, SMOD was the most fun I ever had replaying the HL2 campaign. It wasn’t necessarily the default new settings that made the game fun(ner) but the deep level of intricate customization of random features the modder put in for whatever reason. Most of the features were never really advertised so you had to look deep into the console command lists to discover what potential this mod contains.
    I think my favorite thing was setting the ragdoll physics so that ragdolls sped up instead of eventually slowing down, leading to quickly cartwheel into mach 5, fly off into the skybox, and then explode into a giant blood mist of gibs (this mod had awesome gibs et all)

    Unfortunately, when HL2 and etc switched to the Orange Box engine, the mod broke. I still miss it :'(

  14. GC says:

    Fistful of Frags : Source SDK best western mod

  15. Antsy says:

    Thought this was going to be about a David Frost simulator.

  16. Forceflow says:

    Dystopia was the Source mod I spent most time in …

  17. Alexander Norris says:

    You can’t play mods using Alien Swarm. It doesn’t come with SDK Base.

  18. Pesforozo says:

    The best single player source mod is by far and away Research and Development. Minerva was good, but R&D was Valvelike.

    • Reverend Speed says:

      If not The Specialists for Source, then it has to be Research and Development. Unlike HL2, you actually felt like a scientist! =)

    • westyfield says:

      Yes, Research and Development was excellent and you should all play it. Even though the people I’m replying to have both played it, and therefore will find this advice useless.

  19. Nick says:

    I wish they’d release some stuff for Alien Swarm, I’d happily pay for it.

  20. Schmung says:

    Good news for folk on steamworks. Hopefully means that once they sort dependencies we can just release entirely for free without worrying about explaining to people about source SDK base etc etc. Good times.

  21. mod the world says:

    Empires is the best MP mod, hands down!

  22. airtekh says:

    I liked The Hidden: Source.

  23. Carra says:

    So anyone who owns a Valve game already has access to the SDK.

    What’s the point in making it “free”. Which person interested in PC games development has never played a Valve game? And why would I want to play their games…

  24. Andrige says:

    This bodes well, in my completely deranged mind I think of this announcement as a sign that they are in fact working on a new engine (probably for DotA 2 and Half Life 3) since I find it unlikely that a company like theirs can create new titles without some privately owned engine.

    • steviesteveo says:

      First of: please let there be Half Life 3.

      I don’t really see the privately owned engine as a massive issue. Valve still owns Source after this and it doesn’t hugely matter if other people can make games in an engine as long as you can.

    • JerreyRough says:

      Dota 2 is already in the Source engine.

      Which means mods and custom heroes on certain servers! Yay!

    • skinlo says:

      I know DoTA2 is a slightly upgraded version of the Source engine. Apparently it will have cloth physics in it!

  25. dsi1 says:

    Too bad Occupation CS is a CSS mod :(

  26. R_Yell says:

    Don’t want to sound ungrateful, this is good news but it’s also a big incentive for griefers and hackers. As someone pointed out, what kind of person interested in FPS for PC doesn’t own already a Source powered game? All those people already have installed Source SDK Base. I doubt VAC anti-cheat detects 10% of working cheats, the rest goes undetected. You can ban a steam account from a server or a mod completely if a person is causing mayhem, now they can create unlimited accounts, if I got this right.

    • JerreyRough says:

      You do know that they ban in waves, right? If you ban left and right then they’ll hide and make more obscure hacks. But wait a while and you can get a whole horde of wanna-be hackers at once.

      Also, because of the way games work, you can never actually prevent hacking. You have to change fundamental things that would detract from the entire experience to stop it.

    • pepper says:

      No, not really. It may have a slight use of checking that you got the right functions, but in general you need to go around the processes and calls that the anti cheat program makes, so you want to go a lot deeper then just the SDK level. A good hack consists of moving memory addresses without any punkbuster/VAC program noticing.

      I dont think this has anything to do with steam accounts, they are not tied to the SDK.

    • R_Yell says:

      Don’t know if the point was clear, isn’t about hacking at all but mostly griefing (or just when hacking is very noticeable it becomes griefing as well). You just can ban someone’s account from a server and until now, such person only could buy new games to get more accounts. Just hope Valve can control how many free accounts the same PC can register so this won’t be a big issue in the future.

    • pepper says:

      I see, that wasnt quite clear for me though.

      You got a point there, although I doubt it will be a problem, I havent ever seen it as a problem in other games, except for the fact that assholes will be assholes anyway.

  27. ChiefOfBeef says:

    I for one want to sex Robin Walker’s leg, but I don’t even know how to use SDK to make things.

    If I could I would make a game that is like Ghost Master crossed with Sins Of a Solar Empire.

  28. Kemuel says:

    Maybe I’m being optimistic, but this seems like the sort of thing a company might do before releasing say.. a newer game engine.

    • steviesteveo says:

      I’m the reverse: this seems like the sort of thing a company might do before settling in to use this version of the game engine for a bit longer. You’re just going to annoy people if you hand out SDKs and then shortly after change your game engine. I don’t really see the benefit for Valve in that.

      If they made the whole thing totally public domain that’s a massive clue that they’re coming out with some thing better but they’re just making it free to make games/mods in Source.

    • R_Yell says:

      The right context for this release is probably, just make Steam a bigger gaming platform than it already is. I don’t think many people will develop new Source mods at this point, being UDK and Unity a lot more attractive for students/hobbyists. This isn’t about developing but playing mods.

  29. vivlo says:

    (time for mac whining)
    well. good to know.

    • Raiyan 1.0 says:

      I thought Source is OS X compatible? Shouldn’t you guys get the same goodies?

    • vivlo says:

      i thought too, before buying ; in fact you can’t use source SDK on a mac, only Pc users can make their mods mac compatible. But seen their new policy towards macs, mb if this indeed is the sign of a forthcoming new set of developing tool, then those new tools with be mac compatibles.

  30. kwyjibo says:

    The problem with Source sdk isn’t the price, it’s the tools. Unreal and cryengine are leagues ahead. I’m surprised that people still bother developing on Source.

  31. Inglourious Badger says:

    favourite source mod?
    that would have to be the life-like recreation of my flat I made in Hammer editor, complete with hl2 props including a burnt out bed frame instead of our floweryly-duveted one and a radiator that I couldn’t get to stick to the wall so it just leant against it and fell over when you brushed past

    • Inglourious Badger says:

      I had great plans to use it as the start of a huge L4D level, but alas that whole personal ambition thing faded after about a week.

      Great piece of kit though. Easy to use considering how much it can do. Look up a couple of youtube tutorials and you’re away

    • steviesteveo says:

      There’s not enough really detailed domestic maps in l4dx

  32. Tyrone Slothrop. says:

    Given Valve-Time(tm), we’ll never see a practical and easy-to-use Source SDK/Hammer manipulating a robust, powerful and highly relevant Source Engine.

  33. vash47 says:

    Now if it were actually a good engine…

  34. PleasingFungus says:

    Any word will do that if you hear / read it enough times in a short period. Check it out: link to

  35. msarge says:

    When Unity and UDK decided to go with super cheap licences I thought fit would be great if Valve would do the same with Source. While this sounds similar, it definitely seems like it’s more for the ability to play mods.

  36. Olivaw says:

    So obviously this doesn’t mean everything Valve makes will be free.

    What this means is, they are making a new engine for Episode 3.

    That has to be the reason it’s taken so long! And it would explain all this nonsense about giving away the development kit for their engine and making TF2 free to play and all this nonsense!


  37. JohnnyMaverik says:

    Nightmare House 1&2, Insurgency, the Radiator series, Korsakovia, Dear Esther, Suicide Survival (WHY DOES NOBODY PLAY THAT ANY MORE >.<!!!!!!)

  38. Neoviper says:

    My absolute favorite source mod ever has to be dayhard, a quite old mod made not long after hl2 released. It believe it was the first mod I’d ever played, and it really opened my mind to the possibilities of having those tools available. They’re the reason I’m going to college for game design.

    So do try it out, I’m not sure what the policy on links is here, but just search dayhard mod and it comes up.