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Supported Platforms:
Windows, Mac OS X, Xbox, Xbox360, PS3

Languages Written In:

Languages Supported:

Graphics APIs:
OpenGL, DirectX

  (2 reviews)

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The Valve Source engine technology, the same used to power Half-Life 2, is now available for license by third party developers. Source provides major enhancements in several key areas including character animation, advanced AI, real-world physics, and shader-based rendering. Source offers the most advanced features, tools, and support at extremely competitively prices.

Supported Features


  • Object-Oriented Design
  • Plug-in Architecture
  • Save/Load System
  • Scalability; Dx6-Dx9 hardware supported
  • All code written in C/C++ using Visual Studio 6.0. Easily and quickly derive new entities from existing base classes.
  • Internal context sensitive performance monitoring system
  • Modular code design (via DLL’s) allows swapping out of core components for easy upgrading or code replacement
  • Fixed-function
  • Render-to-Texture
  • 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
  • Server browser: Displays all active game servers and allows a player to choose which one to participate on. Players can filter and sort server lists in order to speed up the display and selection of a server.
  • Friends instant messenger: Allows players to message each other both in and out of the game as well as join friends in existing games. No more confusion about what server your friends are on, you can easily join with this feature.
  • VGUI: Custom GUI interface mimics most of the windows controls but is rendered using the Source engine for both in game and out of game uniform UI display. VGUI is platform independent and is Unicode compliant for ease of localization
  • Environment Mapping
  • Billboarding
  • Particle System
  • Cube and environment mapping
  • Water with refraction and fresnel effects
  • Advanced particle system that can emit sprites or models
  • 3D skyboxes extend the horizon and add parallax on distant objects
  • Dynamically rendered organics (grass, trees etc)
  • Patches


  • Per-vertex
  • Per-pixel
  • Lightmapping
  • Radiosity
  • Gloss maps
  • Dynamic lights, vertex lighting and light maps, many light types including flickering, pulsing etc.
  • High-Dynamic Range lighting
  • Real-time radiosity lighting


  • Shadow Mapping Projected shadows allow for a large number of characters per scene


  • Basic
  • Multi-texturing
  • Bumpmapping
  • Mipmapping diffuse & specular bump maps


  • Vertex
  • Pixel
  • High Level
  • Supports Shaders Version 2.0 and below
  • Dx9 shaders all written in HLSL


  • Mesh Loading
  • Skinning
  • Progressive
  • Deformation
  • 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
  • XSI, Max and Maya .smd exporters for exporting 3D models

Scene Management

  • BSP
  • Portals
  • Occlusion Culling
  • LOD
  • Occluder entities for visibility blocking
  • Indoor/Outdoor environments


  • Skeletal Animation
  • Morphing
  • Facial Animation
  • Animation Blending Layered animation system can synthesize complex animations out of several pieces


  • Rendering
  • CLOD
  • Deformable terrain
  • Effects include but are not limited to: particles, beams, volumetric smoke, sparks, blood, environmental effects like fog and rain


  • Basic Physics
  • Collision Detection
  • Rigid Body
  • More responsive world with realistic interactions
  • Sounds & graphics follow from physics
  • Can be controlled by level design
  • Kinematic animated bone followers
  • Custom procedural physics controllers
  • Vehicle: *Wheels slip and skid, *Realistic suspensions with springs on each wheel, *Individually tunable parameters such as horsepower, gearing, max speed, shift speed, tire material, tire friction, spring tension/dampening etc, *Hovercraft support for cheaper simulation
  • Ragdoll
  • Bouyancy
  • Obeys laws of mass


  • Client-Server
  • 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

Artificial Intelligence

  • Pathfinding
  • Decision Making
  • Finite State Machines
  • Scripted
  • AI characters can interact with physically simulated objects
  • Ropes/cables, machines, constraint systems, ragdoll physics
  • I/O system allowing level designers to control AI
  • Sophisticated navigation: characters that run, fly, jump, crouch, climb stairs and ladders, and burrow underground
  • AI senses things using sight, sound, smell
  • AI relationships determine friend/foe status of other entities
  • Battle AI allows squads of AI characters to operate together, know when to advance, retreat, lay cover fire, etc.


  • 2D Sound
  • 3D Sound
  • 5.1 surround sound, 4 speaker surround and high-quality 3D spatialization
  • Custom software DSP and automatic DSP based on environmental geometry
  • ADPCM decompression
  • 16-bit 44KHz, stereo wave data with all features
  • MP3 decompression (requires Miles license)
  • Support for audio streaming on any wave
  • Real-time wave file stitching
  • Pre-authored Doppler effect encoded waves
  • Pre-authored distance variant encoded waves

Tools & Editors

  • Graphics performance measurement tools built into the engine
  • Faceposer: tool used to craft speech and emotions
  • Valve Hammer Editor: *WYSIWYG World editor, *Create world brushes, *Terrain editor, *Place detailed world models and AI NPCs, *Set navigation points/paths for NPCs, *Place triggers, clip brushes, logic etc., *Allows level designer to hook up I/O between entities to control AI within the game
  • Half-Life Model Viewer: *Full model previewer, *Rotate models in any direction, *Setup hit boxes, *View physics hull, *View normals, *Wireframe, shaded or textured view modes.
  • Studiomdl: Model compiler
  • Vbsp, Vrad, Vvis: Map compilation tools (bsp, lighting and visibility)
  • VMPI: distributed compilation tool allowing level compiles to be spread across many pc’s greatly reducing compile times




License Name Price in $US Source Code Included?
Proprietary Unspecified Yes
Discussed under NDA.

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0 of 0 people found the following review helpful

Good, but not the best.

  by 00000000000000000000000000000000 Methulah Nov 22, 2005 at 10:00

Source is a very popular engine, but at its core, it is essentially a series of Quake hacks. One can even see some original Quake documentation in some areas.

I can only review this from a modding point of view, but I have spoken to some developers who have a full licence. Their experience is similar to mine.

Source engine has a nice set of features, complete with HDR and Facial Animation. It has a very advanced physics engine, that has caused a large stir.

The Source engine uses a shader based pipeline, and thus has some very nice effects. It has refraction, reflection and advanced specular highlights. The material system is very advanced and works itself into the shader system and the physics engine. Materials have "types" which determine the physical effects and how they interact with the world. The bumpmapping in Source is a mojor let down and gives no real appearence of depth.

The lighting in Source is quite nice, especially the HDR. Shadows aren't dynamic, which is a let down for the price. The engine uses soft shadow mapped shadows, which look quite nice, but are unsuitable for many purposes.

The AI is quite nice, but not perfect. It has some issues and needs to be heavily scripted in most instances.

The facial animation system uses muscles, and looks very nice ingame. VALVe has provided tools to facilitate this and it can lead to some very nice sequences.

The netcode for Source is particularly good, even though the physics are sever side, even physics based games manage to run lag free even on basic DSL connections.

Source provides a rounded feature set that is up there with the best. It is let down on some key issues such as shadows and bumpmapping.

-Ease of Use:
Source uses C++ with no scripting support. However, it provides a nice SDK.

Hammer is a BSP based world editor with support for advanced geometry and entities. The compile tools are great and easy to use to get content ingame. The Half-Life model viewer allows developers to view their models ingame without compiling a scene each attempt. A tool for scripting facial animation sequences allows for unprecentented control on lip synch and other aspects ingame.

The SDK works well with Microsoft C++ 7, but is difficult to use under diffrerent IDEs. It is generally easy to use, but has little official documentation, though several modding based sites give tutorials which can help programmers.

-Stability & Performance:
The stability of Source is less than perfect. It has been known to crash and bring up compile errors for no reason in particular.

Source can crash in several instances, and the engine is riddled with anomolies. For example, the engine will crash when the player in Half-Life 2 based games attempts to pick up the scout car with the super gravity gun. While this is a game specific example, it shows the issues with stability that Source suffers for a commercial product.

Performace is decent, even on older machines. Source can be scaled back to DirectX 7, which is impressive for a shader based engine. However, there are several things that negate performance, such as the physics in multiplayer being calculated server side.

From a modding point of view, there is plenty of support from forums that are dedicated to Half-Life 2 modding. For a licenced developer, all accounts say that VALVe are very helpful and prompt with support and provide a top-noch support service that can be accessed 24/7.

The Source Engine was obviously made for Half-Life 2 and is best suited for urban FPS games. It provides quite good features (4.5 if it were possible), and is quite easy to use. It suffers from stability issues, but performs quite well on older systems. From all accounts, the support is top of the range.

If you are looking for publicity on your licence, Source is the engine for you. However, as a engine for serious developers, it is let down by some key issues that make it inferior to other choices.

-Overall Mark: 4.2

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0 of 0 people found the following review helpful


  by 00000000000000000000000000000000 gman Jun 14, 2005 at 19:41

OK I don't have the engine but the SDK together with HL2.
Upon that I made my review.


unmatched by ANY other engine.

Ease of Use:

as far as HAMMER goes along with VC7 - just super

Stability & Performance:

never had any problems with the game or the SDK
Absolutely cool.


The web forum is very good, and I can not complain.

ps. my name is NOT gman but isn't he cool, hey?

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Last edited Dec 28, 2011 at 13:11

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