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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The Gameplay

proto 2fort tf20001

In Team Fortress 2: Invasion, the goal is to collect the most resources you can. Resources can be gained by killing enemies, destroying enemy equipment, or collecting resources from a Resource Pump.

Instead of rounds, each conflict is called an Act. Act time limits are set by the mapper.

Weapons are more accurate when crouching.

You can build Vehicles at Vehicle Bays.


The classes of Team Fortress 2 Invasion are somewhat similar, but still different from their original counterparts from TFC and present day TF2.

The Commando

Armed with a shield and a laser rifle, the Commando is a good class for support against the enemy team. This class is pretty quick. This class is only able to build a Powerpack, and a wagon if you're on the Alien team. Can kick enemies to the ground when close to them.

The Defender

Armed with a Minigun, this is a slow and heavy class that is good to provide defense against the enemy team by building various defensive structures and by fending them off with the Minigun. This class can build a Powerpack, Bunker, Barbed wire, Dragon's teeth (?), Sentry Gun, and a Manned Missle Launcher. This class is recommended for those that want bullets to fly.

The Escort

The Escort's main purpose is to protect surrounding teammates using a large shield he controls, which has two different tracking methods. This class can build a Bunker, Sandbag bunker, and a Manned Missle Launcher.

The Medic

Armed with a burst rifle and his trusty Repair Gun, the Medic can heal teammates and repair damaged team buildings. The Medic can build a Sandbag Bunker, Resupply Station, Buff Station, and the Powerpack.

The Pyro

The Pyro's main purpose may be to burn enemies and destroy enemy equipment, The Pyro can pour gas and light it later, which can be very useful for setting traps. The Pyro is armed with a Gas Can, Flamethrower, Grenade Launcher, and a pistol.

The Technician/Sapper

Armed with a Shotgun, Rallyflag Placer, and a Rocket Launcher, the Sapper specializes in both offense and defense. The Sapper can construct a Resource Pump to increase their team's Resource Bank. Can build a Sandbag Bunker, Powerpack, Manned Plasma Gun, Resource Pump, and Dragon's Teeth. The Sapper is the engineer of Team Fortress 2: Invasion.

The Sniper

Armed with his Sniper Rifle and Limpit Mines, the Sniper is a good class to use to quickly and effectively take out enemy players. When standing still for a period of time, the Sniper can become completely invisible, but only when your team had enough resources. Cannot build anything.

The Recon

A fast, unarmed class. The Recon is good for scouting out enemy players and resources, and also can track enemies that are within a certain radius from the Recon and shows them on the map. This class may have a mechanical, metal glove to be used to punch enemies, each punch charges a stronger electric punch. This class currently does not work and crashes the game. May be fixed for next update.

The Support

Very broken, meant to be the Demoman of Team Fortress 2: Invasion. Or possibly just meant for testing.


This class is not a man, but is a robot disguised as a spy. Can disguise as an enemy player, silently kill players, consume corpses if your team has enough resources, and had thermal vision. Good for getting resources without anybody noticing. Can't build anything.



The Powerpack can supply up to 3 nearby objects with energy until it's destroyed. Good for keeping your buildings protected while away.

Sentry Gun

Able to find and quickly eliminate enemies by shooting high-speed plasma projectiles. Good for keeping enemies out of your team's base.

Buff Station

This object can heal up to 4 players connected to it. A connected is indicated by a wire or tube attached to the player from the Buff Station. If the player moves out of radius, the connection to the Buff Station is lost. Good for players that need healing while the medic is off doing something else.

Barbed Wire

Although the name doesn't sound as cool, the Barbed Wire is good for keeping out enemies from places you don't need them in. When two barbed wire are placed close to each other, it generates a deadly laser in between them.


Good for keeping cover from enemy fire and also good for protecting vehicles and infantry against enemy projectiles.

Sandbag Bunker

Although not as strong as the Bunker, this is good for keeping cover while still attacking enemies, and provides good cover from enemy projectiles.



good for getting places quickly, but isn't very powerful. Recommended use is for transportation only.

Battering Ram

If you wanna get places and kill enemies at the same time, this vehicle is for you. Pretty strong against enemy corpses and bodies.


Slow, but good for defending your team's base from oncoming enemies. Shoots missles at a slow fire rate.

Teleport Station

Not much of a vehicle, but can be built at Vehicle Bays like all the others. good for trying to get your teammates somewhere quickly, if you're willing to take the risk of placing them to said place.


Similar to the Tripods from War of the Worlds, these are tall, lengthy vehicles that move slow but are good for trying to kill enemies, as it provides cover and transportation at the same time. Alien team only


Just like the Strider, but smaller in size. Uses up less resources, and is pretty good if you have enough to build it, but if you have enough to build a normal Strider, the normal Strider is recommended. Also only for the Alien team.

Development Progress

TF2 Invasion is currently on Patch 5, and is really not all that playable right now. But we plan for Patch 6 to be the biggest update both aesthetically and gameplay-wise.

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To bad this engine was not coded to count beyond the number three.

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man, i love source :3

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can anyone link me an up to date tutorial on how to make mods for the source engine beyond going into source sdk and clicking create a mod the best link I have found so far is the my first mod article in the valve developer community however for the prepare the solution section I got very confused as the only version of visual studio I have is 2015 but it only goes up to 2012

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check crimewarssource youtube vids

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anyone know what engine i should use to make my own game

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That is a stupid question because no one can know what engine is the best for "your game", all we can do is suggest the engine we like the most, but sometimes what we like is not "the best".
The only way for you to know, what is the best engine for your game, is for you to experiment with them, and imo the best engine for any game, is the engine we as a developer/moder know the best, trying to find a engine perfect for your game is stupid and is the reason that many wannabe game developers never release anything.

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Ratings closed.

Highest Rated (19 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 by Half_Kill


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