The Source Engine is a 3D game engine developed by Valve Corporation. Its unique features include a large degree of modularity and flexibility, an artist-driven, shader-based renderer, accurate lip sync and facial expression technology, and a powerful, efficient and completely network-enabled physics system. 

The Source engine was first shown to the world by being the power-horse behind the hugely anticipated Half-Life 2 which was released in late 2004. Since then the Source Engine has been upgraded with the release of such titles as Half-Life 2: Lost Coast, Team Fortress 2 and the Left 4 Dead series to name a few.

Whilst it has been years since the release of the Source Engine they haven't yet unveiled a 'next-generation engine' as the Source engine is always updating and is just as relevant in the gaming world today if not more than when it debuted in 2004. It has been aided by the release of the free Source Development Kit (SDK) which include such features as HDR for developers to use in their projects. Hence the reasons stated we have yet to see 'Source Engine 2'.

On July 10th 2012, Valve released the 'Source Filmmaker' - a freeware client to allowed anyone to make movies inside the Source Engine. More information on the Source Filmmaker can be found here.

Below you can find a list of amazing features that the Source Engine boasts:


  • Version 2.0 (and below) shaders, bump mapping, LOD on models and world
  • Author shaders with HLSL
  • Cube and environment mapping
  • Dynamic lights, vertex lighting and light maps, many light types including flickering, pulsing etc.
  • High-Dynamic Range lighting
  • Water with refraction and fresnel effects
  • Advanced particle system that can emit sprites or models
  • Projected shadows allow for a large number of characters per scene
  • Occluder entities for visibility blocking
  • Indoor/Outdoor environments
  • Deformable terrain
  • 3D skyboxes extend the horizon and add parallax on distant objects
  • Dynamically rendered organics (grass, trees etc)
  • Subdivision surfaces, diffuse & specular bump maps
  • Real-time radiosity lighting
  • Effects include but are not limited to: particles, beams, volumetric smoke, sparks, blood, environmental effects like fog and rain
  • Scalability
  • Dx6-Dx9 hardware supported

Materials System

  • Instead of traditional textures, Source defines sets of materials that specify what the object is made from and the texture used for that object. A material specifies how an object will fracture when broken, what it will sound like when broken or dragged across another surface, and what that object’s mass and buoyancy are. This system is much more flexible than other texture only based systems.
  • Materials can interact with objects or NPCs such as mud or ice for vehicles to slide/lose traction on.

Multiplayer Network Code

  • Time and gamer tested by millions of gamers around the world
  • Support for both LAN based multiplayer and Internet based multiplayer games
  • Prediction analysis for interpolating collision/hit detection
  • Optimizations for high-latency, high-packet loss 56k connections

Advanced Characters

  • Detailed and believable characters
  • Realistic eyes
  • Focus on player/object, not simply parallel views
  • Proper eye “bulge” for realistic eye reflections
  • Simulated musculature provides outstanding emotions, speech and body language
  • Language independent speech, characters can naturally speak in many languages
  • Skeletal/bone system for animation
  • Layered animation system can synthesize complex animations out of several pieces
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Blog RSS Feed Report abuse Latest News: Contagion - Full Release out now!

About Contagion with 15 comments by Tatsur0 on Apr 15th, 2014

We're excited to announce that Contagion is no longer in Beta or "Early Access" anymore but now a Newly Released Full Game! We're very excited but of course nervous though the reception has been very positive and we hope to keep it so as we are working on releasing quite a bit throughout the week and the Contagion SDK this Sunday for our modding community! We'd also like to share (we know the animation is a bit off but this has more to do with the fact that we've finally bridged the gap between Non-Valve Games and SFM) our Cinematic SFM Release Trailer. We hope you enjoy! For those who are/were big in the modding scene the Music is done by our very own Ed Harrison (NeoTokyo)!

Contagion - Full Release
Contagion - Full Release
Contagion - Full Release
Contagion - Full Release

Release being the big deal that it is we decided to go big with a competition that would launch with the release of Contagion! We've done all kinds of challenges/competitions and they tend to rarely connect with enough users so we wanted to do something that pretty much everyone could partake in with a fairly equal shot at winning. We're currently holding an Official Contagion - Let's Play Competition with prizes exceeding $12,500 USD. All you need is a copy of Contagion and a Youtube account. Check out this instructional video for more information and/or visit Contagion-game

We started so small so long ago, then came ModDB and things picked up, ZPS grew into a very popular mod but couldn't have happened without Twilight and Rhone from ZP1, and now we've got Contagion on IndieDB which took 2nd place after Starbound. We've got a great community and a great place we all call home whether it be ModDB/IndieDB/SlideDB. Want to thank everyone here for those that showed their support and made this possible. To some it's not a big deal but for us our first Fully Released Indie title means a great deal. Thank you!

-The Contagion Team

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Post comment Comments  (290 - 300 of 309)
GisleAune Jul 4 2008, 3:26pm says:

Source is the best game engine EVER!!!!!

The bump mapping is GREAT, the capabilities is GREAT!!!!

keep up your good work on HL2 EP3

+5 votes     reply to comment
mr_peters Jun 13 2008, 6:47pm says:

just great... and they are using games in it that i have played/playing... feels like this clip is about a part of my life, or whats gonna happen to my life if i keep sitting at my comp 10 h each day xD, well, **** happens and im still 15 years old ;)

+1 vote     reply to comment
HunGub May 25 2008, 6:16am says:


-1 votes     reply to comment
LORDDEREX Jun 10 2008, 11:03am replied:

u cant download Source Engine u need to buy games like Half-Life 2 and u get Source SDK with it

0 votes     reply to comment
jazminas May 11 2008, 7:55am says:

there i can get this engine?

-1 votes     reply to comment
viper276 May 6 2008, 12:33pm says:

this is one of the best engines ever used for games

+5 votes     reply to comment
LORDDEREX May 18 2008, 12:54pm replied:

Source is the best for realism-made games!

+5 votes     reply to comment
viper7x Mar 5 2008, 1:26pm says:

Here, I have half life 2 (orange box) but I can't see to find out how to get hold of the engine. Is it possible to do this and if so where would i find it.

+2 votes     reply to comment
da_newb Mar 5 2008, 5:38pm replied:

Open up Steam and on the top where there are all the tabs click tools. Then click on Source SDK and click on install in the bottom right. I would also recommend installing the bases. I think some mods utilize them in some way. I might be mistaken though.

+4 votes     reply to comment
comrade_grunt Apr 1 2008, 2:35pm replied:

The doom engine :V

0 votes     reply to comment
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Release Date
Released Oct 31, 2004
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Highest Rated (16 agree) 10/10

Even tho it is aging and it is beginning to show its weakness comparred to other more modern engines, it is still my most preferred engine and the only one I was able to get into succesfully. And with all of the updates Valve is giving it, I think the source engine will be with us for a long time. I wouldn't really recommend this for a commerical product, just because there are so many more modern engines out there that will be a lot easier in the long run (like UDK), but all of the commercial games…

Nov 16 2010, 3:48pm by Half_Kill

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