Since 2006’a Gears of War, Epic Games’ Unreal Engine 3 has provided both console and PC gamers hours of game play packed with graphical prowess. The now 5 year old graphics engine has enjoyed constant evolution to remain viable. At 2011’s Games Developers Conference, Epic Games unvieled its Samaritan demo, proving to the world that not only could Unreal Engine 3 deliver graphics capable of fully utilizing current gen hardware but a huge evolution in graphical prowess that would require next gen hardware to in order to utilize all of it’s features.
Using a three-way SLI GTX 580 powered gaming system, Epic Games was able to showcase some of the engine’s newest features. Taking eight months of development, the engine contains a slew of lighting, reflection, and shadow improvements as well as realistic hair and cloth physics.
Bokeh Depth of Field has been a popular artistic choice in Hollywood Films for many years. Seen as out of focus but identifiable colored shapes in the background, bokeh objects serve to enhance a scene and influence viewers’ moods. Epic was able to improve upon earlier methods of rendering bokeh objects, though they admit that real time rendering of bokeh objects as seen in Hollywood films will necessitate next gen hardware. Currently, the bokeh effects will be best used in cutscenes where developers can control and pre-render the objects to the best storytelling effect.
Epic has also greatly enhanced the ways that light and reflections are handled. Collectively called Image Based Reflections, Epic has implemented Point Light and Billboard Reflections. These are then coupled with both static and dynamic Reflection Shadows to achieve a look resembling the real world. While the graphics horsepower is not available today to allow Epic to mirror the way light works in the real world exactly, they are able to achieve a very close representation. For example, they are not able to render the road to be as detailed as real life. The road shown in their Samaritin demo was much less un-uniform. This is so because the hardware required to calculate reflections on a road as un-uniform as in real life (in real time) is simply not available today.
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Static Reflection Shadows are used to render objects in the level that are not moving (such as buildings) while the dynamic variant is applied to moving objects such as the player and NPCs. These Reflection Shadows control light bleed, and ensure a realistic game world. You can see the benefits of Reflection Shadows in the following image. Using Epic’s new method, lights and shadows act more like their real world counterparts.
In games, humans –and their faces in particular– have always been difficult to render realistically. Especially in real time, the concessions that have had to be made generally result in a waxy or plastic appearance due to the way light has traditionally lit characters’ faces. Epic has developed a new way to achieve realistic faces in real time that they call Subsurface Scattering. Subsurface Scattering moves the light reflections of characters’ faces from on top of the skin to beneath the skin, resulting in a more uniform and realistic look. Instead of light bouncing off of the skin itself, the reflection is moved under the skin and a defraction layer is applied to scatter the reflection. This method creates more realistic model with believable skin tones (keep in mind that real skin is also somewhat translucent). Further, hair is made more realistic with the help of vertex shaders in a process called Camera Aligned Triangle Strips. By extedning hair splines using vertex shaders into thousands of triangles, Epic is able to model realistic looking hair without requiring inordinant amounts of processing power. Each hair is also capable of independantly reflecting light and causing shadows.
The Samaritan in Epic’s video demo wears a dark trench coat. In order to maintain the suspension of disbelief of the game world, Epic wanted to model the coat to act with realistic physics, especially in scenes where the character was performing acrobatic moves. As the character jumps from the rooftop onto a police officer, his trench coat billows up behind him. As he engages the other enemies, it moves fluidly around him. This modeling is done using a Nvidia technology in the Unreal Engine called APEX.
Further features included in Unreal Engine 3 thanks to DirectX 11 include:
- Tessellation and displacement
- Geometry shaders
- Multisampled textures
- Shader Model 5
According to GeForce, "Tim Sweeney says, ‘everything shown in the Samaritan demo is intended to showcase both next-generation console possibilities and DirectX 11 on today’s high-end PCs,’ and though he admits, ‘bits of it – such as cloth and some post-processing effects – are technologically compatible with current-gen consoles,’ he believes that ‘the sheer magnitude of its usage in Samaritan goes far beyond.’"
This statement indicates that Epic believes UE 3 is still a solid platform and will be around for some time to come. The new features that they have implemented certainly warrants its usage with current and next generation hardware. Tim Sweeny states that at one point hardware will advance far enough that the best of Unreal Engine 3 will be re-architected and evolve into the next iteration of Unreal Engine.
Now that developers have realized the current generation of consoles have reached their limits, they may be more inclined to try out the new Unreal Engine 3 features in PC versions of their games in an effort to advance their artwork and storytelling to the next level. Once the next generation of consoles are released, developers will have even more incentive to implement these realistic lighting and shadow improvements.
Until games have been released that implement these features, you can get an idea of the improvements in Epic’s Samaritan video demo below as well as using the UDK to develop your own games.