Rendering

High-performance support for five basic rendering primitives:

• BSP geometry.  Built using Constructive Solid Geometry (CSG) primitives, BSP is the primary tool for shaping interior environments.
• Static meshes.  High polygon-count objects built and textured in an external modeling program such as 3D Studio Max, XSI and Maya, suitable for using as building blocks for constructing levels.
• Animated skeletal meshes.   Characters, weapons, and other meshes use skeletal animations imported from external animation tools like XSI, 3D Studio Max, and Maya.
• Vertex meshes.  The engine also supports keyframed vertex-animated objects when needed.
• Height-Mapped Terrain.  Terrain is stored as a height field, which can be manipulated easily as an image in external tools, or manipulated in real time in the Unreal editor.
  
  

Unreal Engine 2's advanced portal rendering system supports:

• Mirror surfaces and semi-reflective materials such as marble.
• Non-Euclidean, redirectable "warp" portal effects for seeing into non-contiguous regions of space.
• Skies and backgrounds with independent coordinate systems for independent translation and rotation.
• Visible Surface Determination system supports high-performance, seamlessly-interconnected indoor and outdoor scenes, providing designers with tools such as portals and occluder volumes to optimize rendering performance.
• Full support for DirectX8 class video cards (including ATI® RADEON™- and NVIDIA® GeForce™-class cards).
• Fallback rendering support for DirectX6 video cards as far back as the NVidia TNT.
• Rendering subsystems include Direct3D, OpenGL, and RAD Game Tools' Pixomatic software renderer for Windows PCs – bundled with Unreal Engine 2 at no additional cost. The inclusion of software rendering guarantees that any PC with a reasonable CPU will be able to run Unreal Engine 2, regardless of 3D card support.
• Unreal Tournament 2004 (and 2003) are used by numerous industry publications and websites as benchmarks for PC system capabilities.
  
  
  
  

Animation

• Supports up to 4 bone influences per vertex, with no hard-coded limits on polygon counts and bone counts.
• Hierarchical skeletal animated, smooth-skinned geometry support for animated characters and complex animated geometry in game environments.
• Multiple channels of animation, each with a variable blending factor and starting bone, allows for multiple animations to be played simultaneously.
• Skeletal Keyframe interpolation support for perfectly fluid animation independent of frame rate.
• Tweening support allows smooth flow between disjoint animation sequences.
• Artist-controlled compression reduces memory usage.
  
  

Lighting

• Supports dynamic lighting on all geometry types with vertex lighting and projective texturing. Any object in the world can act as a static or dynamic light.
• High-quality pre-computed lighting via RGB colored light maps and an optional vertex lighting channel.
• Supports directional lights, point lights and spot lights.
• Projected textures allow the simulation of complex dynamic lighting and shadowing effects on all surfaces, including player shadows and flashlights.
• Numerous light effects for dynamic lights including blinking and wavering.
  
  

Effects

• Comprehensive particle system allows for countless diverse configurations, supporting particles composed of sprites, meshes, lines, and beams.  Particles support a multitude of lifetime, texture, and movement options, including collision where needed.  All particle features can be manipulated in realtime in the editor

• Fluid surfaces support dynamic water simulation, with ambient ripples, targeted oscillations (for footsteps, explosions, or other disturbances), clamping for realistic wave boundaries, and surface vertex alpha blending for texture effects.

• Distance fog provides a sense of depth indoors and out, while improving rendering performance in large outdoor areas via far-clipping.
  
  

Terrain

Height Map terrain system allows for fast, complex terrain rendering supporting multiple, seamlessly-blended layers of:

• Alpha-blended textures.
• Decoration layers for flora detail and other procedurally-placed meshes.
• Comprehensive suite of terrain manipulation tools allows you to raise, lower, raze and flower the heightmap in real time.
• Supports artist-controlled terrain cell removal, for smoothly transitioning from height-mapped terrain to indoor areas such as caves and buildings.
  
  

Textures

• Material system allows for alpha-blending and modulation of multiple layers of textures with artist-controlled blending and panning operations.
• Easy-to-use mechanism for scrolling, rotating, and scaling textures via artist settings. This feature can be used in a static or dynamic fashion for elaborate animated effects.
• Detail textures add extremely close-up details to surfaces, such as fine wood grain, pock marks on brick surfaces, or scoring to metal.
• Hardware accelerated, compressed, high resolution texture support allows for individual 32-bit textures of up to 2048x2048 pixels in size, while consuming significantly less video and system memory than traditional RGBA or 8-bit texture formats.
• All textures support up to twelve levels of mip-mapping, including mipping down to a solid color.
• Texture animation sequences with variable playback rate.

Sound

• Standards-compliant OpenAL based audio subsystem on Windows, Linux and Macintosh; support for native console sound.
• Supports 3D spatialization, attenuation, pitch and Doppler shifting.
• Supports EAX 3.0 effects on compatible cards, exposed to both level designers via UnrealEd and programmers via UnrealScript.
• Ogg Vorbis streaming sound and music support on Windows, Linux and Macintosh, offering higher quality audio with smaller file sizes than MP3, without royalties; Windows Media Audio on Xbox.
• Includes OpenAL wrapper with 100% software fallback path for utmost compatibility on Windows, Linux and Macintosh.
• Dolby DigitalTM Surround Sound certifiable.
• Offers a unified solution for hardware sound acceleration; it natively supports Creative Lab's EAX 3.0, and falls back cleanly to EAX 2.0 if the user's system does not support EAX 3.0 features.
• Integrated music playback, including support for user-provided tracks.
• MP3 support with the Miles library (licensed separately).

Voice Support

Unreal Engine 2 offers complete voice support, including:

• Voice-over-IP.  Players can communicate with other players using natural voice, with support for multiple channels and encoding options.
• Text-to-speech support.  For players without a microphone headset, the Unreal engine offers an excellent voice synthesizing system.
• AI speech recognition.  Bots in Unreal Tournament 2004 can recognize simple voice commands for changing battlefield tactics.

Gameplay features

Vehicles

Movie Recording

• Unreal Engine 2 supports recording of in-game footage as replayable ‘demo' files, which can be shared between game players in your community to show off play techniques.  It's also an extremely useful feature for distributed product testing. 
• Includes support for processing those demo files into DivX movies. (The DivX integration code is freely available to licensees, but use of the DivX libraries must be licensed separately.)

UnrealEd Content Creation Tool

• The Unreal Editor (UnrealEd) is a pure “What You See Is What You Get” content creation tool filling the void between XSI, 3D Studio Max and Maya, and shippable game content.
• Real-time level design tool based on constructive solid geometry, optimized through its use in multiple released games for building real-time 3D environments.
• UnrealEd is fully integrated into the Unreal engine: the in-editor camera views are identical to the in-game views. All texture placement, geometry, and lighting operations (except shadowing) take place immediately, providing extremely fast feedback while building levels.
• Visual, hierarchical object property editor for customizing actors placed in levels; easily extensible by programmers via script.
• You are always one mouse click away from play-testing your level on both PC and Xbox.
• Tabbed "browser" windows allow fast and easy selection and manipulation of geometry and content
• Realtime “Matinee” cinematic editor for comprehensive camera, actor, and effects direction – for in-game cinematics and pure machinima-style movies.
• Max/Maya/XSI Export Tools. We provide plug-ins for 3D Studio Max, Maya and XSI to bring models into the Unreal engine with mesh topology, mapping coordinates, smoothing groups, material names, skeleton structure, and skeletal animation data.
  
  
  

Physics

Integrated Karma rigid body physics engine bundled with Unreal Engine 2 at no extra cost, supporting:

• Ragdoll skeletal character animation.
• Vehicle physics, including Internet multiplayer support.
• Physically interactive game objects.

• Integrated physics-driven animation eases network programming and animation replication.
• Supports a variety of collision primitives allowing designers to make fine tradeoffs between performance and accuracy.
  
  

AI

• Built-in state-based AI support for game actors, ranging from cannon-fodder creatures to NPC's and teammates.
• Pathnode-based AI navigation system supports complex route evaluation, alarm points, and more.
• Navigation framework enables NPC's to select optimal paths through levels based on flexible criteria.
• Navigation framework is aware of obstructions and gameplay features; NPC's know how to use switches, ladders, lifts, and doors as necessary while following paths.
• Animation system ties into AI via notification system, with animation playing, blending, tweening, looping, and other triggers, such as footstep sounds.
• AI properties are exposed to level designers for setting up patrol routes, individual creature moods and more.
• Extensible framework for making NPC's aware of all player movement options, weapons, and inventory.
• Includes Unreal Tournament 2004's high-level team-based and individual AI framework for objective-based first person shooters.

Networking

Internet and LAN play has been a hallmark of Epic's past competitive games such as Unreal Tournament 2004. The Unreal Engine has long provided a flexible and high-level network architecture suitable to many genres of games.

• Supported on all PC and console platforms.
• Unreal Engine gameplay network programming is high-level and data-driven, allowing UnrealScript game code to specify variables and functions to be replicated between client and server to maintain a consistent approximation of game state.
• The low-level game networking transport is UDP-based and combines reliable and unreliable transmission schemes to optimize gameplay, even in low-bandwidth and high-latency scenarios.
• Client-server model supporting up to 64 players as provided. Also supports non-dedicated server (peer-to-peer mode) with up to 16 players.
• Supports network play between different platforms (i.e. dedicated PC serving console clients; Windows, MacOS and Linux clients playing together.)
• All gameplay features are supported in networking, enabling vehicle-based multiplayer games, competitive team games with NPC's or bots, cooperative play in a single player focused game, etc.
• Support for auto-downloading and caching content, including cross-platform compatible UnrealScript code. This feature enables everything from user-created maps, to bonus packs, to complete game mods to be downloaded on the fly. .
• In-game server browser GUI for finding and querying servers, keeping track of favorites, in-game chat, etc.
• A “master server” component is provided for tracking worldwide servers, providing filtered server lists to players, etc.
• Worldwide game stats tracking system.
  
  

Please note that we don't provide a MMORPG server or networking framework suitable for massive multiplayer games. Though such a task is a multi man-year engineering effort, several teams using the Unreal Engine have done so (including NCSoft for Lineage II and Electronic Arts for Ultima X), demonstrating the feasibility of using the Unreal Engine as a MMORPG game client and tools pipeline, integrated with a proprietary server component.

Platforms

• Unreal Engine 2 offers broadened hardware and software compatibility; it runs at acceptable frame rates on graphics cards shipped in 1999, and even runs on fast machines with integrated graphics through optimized software rendering libraries.
• While Windows XP is the primary development and deployment platform for Unreal Engine 2, the Unreal Tournament product family has long been known for support for other operating systems.
• Unreal Tournament 2004 is no exception, with full server and client support for both Linux and Macintosh's OS X.
• Unreal Engine 2 is also already compatible with next-generation operating systems such as 64-bit Windows and 64-bit Linux.

Console Support & Portability

• Fully optimized for and supported on Windows and Xbox.
• Optimized seek-free DVD-based loading support for Xbox.
• Fully functioning source code available for PlayStation2.
• Fully functioning source code available for 64-bit Windows, MacOS X, Linux 32-bit and 64-bit.
• Highly modular, object-oriented foundation with few hard coded limits maintains portability and allows the Unreal engine to evolve through many generations of technological advances.

General Programming

• Unreal Engine 2 includes example content and 100% of the source code for the engine, editor, XSI/Max/Maya exporters, and the game-specific code for our internally-developed games.
• Extensible, object-oriented C++ engine with software framework for persistence, dynamic loading of code and content, portability, debugging.
• UnrealScript gameplay scripting language provides automatic support for metadata; garbage collection; profiling; persistence with very flexible file format backwards-compatibility; support for exposing script properties to level designers in UnrealEd; a GUI-based script debugger; and native language support for many concepts important in gameplay programming, such as dynamically scoped state machines and time-based (latent) execution of code.
• Localization. Unreal Engine 2 is based on the Unicode character set, and has full support for 16-bit Unicode fonts and text input, including importing TrueType fonts into renderable bitmap fonts. The programming and content environments are localization-aware, with a simple framework for externalizing all game text. Our past games have shipped in 9 languages including Japanese, Chinese, and Korean.
  
  

Typical Content Specifications

Here are the guidelines we used in building content for Unreal Tournament 2004, one of the most recently shipped Unreal Engine 2 games. Different genres of games will have widely varying expectations of player counts, scene size, and performance – and PC capabilities increase over time, so these specifications should be regarded as one data point for one project rather than as mandatory specifications.

• Characters: Our typical characters contain 2000-3000 triangles, and are mapped with one texture in compressed DXT1 or DXT4 format at a typical resolution of 512x512 or 1024x1024.
• Bones: Typical characters have 30-60 bones.
• Typical static meshes typically contain 300-3000 triangles, and are mapped with one texture of resolution 512x512 or 1024x1024.
• Environments: Typical environments have 150-300 objects in view, for a total count of 50,000 to 150,000 triangles in view.
• Terrain: Height maps are typically 128x128 to 256x256 in resolution; typical terrain has 4-10 alpha layers.

Unreal Engine 2X

Overview

Unreal Engine 2X is the highly optimized engine behind the eye-popping visuals seen in Unreal Championship 2: The Liandri Conflict. UE2X pushes 3-4 times the polygons of the original Unreal Championship game, and in fact outperforms most current generation PC games even though they run on much faster CPUs. Couple that polygon throughput with its advanced material shader system and you have an engine that showcases the Xbox's potential.

Graphics Enhancements

Unreal Engine 2X supports both the Direct3D fixed function pipeline and the fully programmable pipeline. It has both vertex shader and pixel shader support. The vertex shader support, which it uses for hardware skinning, enables large numbers of animated meshes on screen at once. Its pixel shader materials push the limits of what can be done on an Xbox, giving you many advanced effects at your disposal.

Full Scene Light Bloom and Emissive Materials

Both emissive materials (materials that appear to emit light) and full screen light blooming are two of the post processing effects that Unreal Engine 2X supports. The full screen light bloom uses the luminance of pixels in the scene to determine whether or not they are “hot.” “Hot” pixels are then manipulated using image space techniques resulting in a soft light blooming effect. Emissive materials are handled in a similar way, except that which portions of an object that give off light are completely under the control of an artist.

Depth of field

Image Space Effects

Distortion, controllable filter kernel blurs, radial blurs, and color space manipulation are some of the image space effects supported by Unreal Engine 2X. Distortion can even be applied on arbitrary geometry, for dynamic explosions, character effects, and the like.

Dynamic Gamma

Dynamic gamma correction is used to keep textures crisp on televisions and is used to calculate the overall luminance of a scene for light blooming (an ocular adjustment effect).

Advanced Projected Lighting/Textures

Unreal Engine 2X improves projectors by handling them on the GPU to free up precious CPU cycles. Additionally, projector rendering batches multiple projectors into a single pass using specialized vertex and pixel shaders.

Efficient Player Shadows

Unreal Engine 2X uses special texture formats to make higher resolution shadows affordable on the Xbox. These shadows are 1/4 th the memory of the same resolution shadow without this optimization. Also, an optimized render path is used to give nice soft edges without multiple passes.

Memory Enhancements

Efficient Geometry Storage

Throughout the development of Unreal Engine 2X, we have paid special attention to the reduced console memory footprint. We've made creative use of vertex shaders to decompress all geometry on the GPU, during run-time. Areas receiving special attention include static mesh (object) geometry, terrain geometry, skeletal mesh (character) geometry, and BSP (world) geometry. We also have enhanced the engine to allow sharing of animation data across differing skeletons and skeletal meshes.

Instanced Content

It also supports instancing of world meshes, animated meshes, and particle systems. Instancing these types of objects lets you place more of them in your environment with less memory and CPU cost than non-instanced methods.

Memory Tracking

Because memory is so critical for console development, Unreal Engine 2X offers a variety of tools for better tracking of memory consumption, including leak detection.

Additional Features

Split-Screen Rendering

Unreal Engine 2X supports 2- and 4-port split-screen rendering, as well as arbitrary viewports for picture-in-picture effects. These split-screen modes work seamlessly across the network, and in fact share rendering and networking tasks for optimal consumption of GPU and network resources. If necessary for your title, UE2X also provides scalable options for increasing frame rate by reduced rendering fidelity on static meshes, particle systems, characters.

Vehicle Support

The vehicle systems from the award-winning Unreal Tournament 2004 Onslaught game, developed on Unreal Engine 2.5, are also available in Unreal Engine 2X.

GUI System and Editor

Unreal Engine 2X uses an Xbox-optimized version of the GUI library that shipped with Unreal Tournament 2004. This includes support for the editing suite, which allow menu layout in real time. The UE2X GUI system also integrates seamlessly with UIX, Microsoft's skinnable user interface for Xbox Live. The GUI supports most standard widgets, plus numerous complex objects such as streaming videos, but it is also easily extensible by teams with special needs.

“Prefabricated” Unreal Matinee Sequences

Unreal Engine 2X allows creation and reuse of Unreal Matinee sequences, such as camera movement, depth of field effects, etc. These sequences can be invoked on the fly, during gameplay, and they automatically adjust to work within the constraints of the geometry in that area. Unreal Championship 2 uses this feature for on-the-spot ‘death blow' animations, triggerable in-game cinematics, and the like.

Underneath the Hood

It also supports all the Xbox-specific features you would expect:

• Xbox Live networking and voice
• UIX library support for quick Xbox Live integration
• PIX groups support for graphics performance investigation and debugging
• XACT, the Xbox sound library and editing tools
• XMV movie support, including using movies for arbitrary materials on any surface

Throughout the engine, we've made optimal use of proprietary NVIDIA and Xbox hardware that we can't discuss on this public website. Licensed Xbox developers should feel free to contact us for more details