Tech Focus: LucasArts moves to Unreal Engine
Digital Foundry compares UE3 to the studio's existing technology
It's official: last week, LucasArts signed a long term, studio-wide deal that sees the developer licensing Epic's Unreal Engine 3 technology.
"Unreal Engine 3 is a forward-looking solution that shortens the path between inspiration and execution on a wide variety of gaming platforms," said Zak Phelps, director of technology at LucasArts. "We are thrilled to add another exceptional tool to our technology mix."
This is undoubtedly great business for Epic Games, facing increasing competition in the engine/middleware space, and we can assume that LucasArts is set to benefit from a more cost-effective means in bringing its games to market. On the other hand, implementing middleware company-wide may suggest that jobs may be affected. As Sony Santa Monica's director of technology Christer Ericson put it on his Twitter feed:
"LucasArts signs multi-year Unreal Engine 3 deal. In other news: LucasArts programmers, Sony Santa Monica is hiring!"
From a technological perspective, the studio's last big title - Star Wars: The Force Unleashed II - is a seriously impressive piece of work, and while the game is far from perfect, its issues are far more to do with design than they are with the core engine tech. In fact, we'd venture to suggest that it would take extensive re-development of Unreal Engine 3 to match the level of technical accomplishment LucasArts shipped with on its The Force Unleashed II Xbox 360 and PlayStation 3 SKUs.
Key to the visual look of The Force Unleashed II is the implementation of deferred rendering, allowing Lucas to employ far more light sources than traditional forward renderers. The standard technique for a multi-pass forward renderer like Unreal Engine 3 is to consider the scene several times dependent on the amount of lights, and how they affect each object on-screen. Essentially, the more lights that are in play, the costlier the impact on rendering time.
With a deferred lighting renderer, the composition of the frame is split up into a series of different render targets or frame buffers that cover off particular surface properties in the scene. These are then combined for the final image. There are processing and RAM implications, but hundreds of different light sources can be generated, transforming the look of the game.
Some of console gaming's most technologically advanced titles use a fully deferred approach, including hits such as the PS3 Killzone titles, Crysis 2, Need for Speed: Hot Pursuit and all the titles being developed on the Frostbite 2 platform (Battlefield 3 and more). Others, including SHIFT 2, Blur, GTA IV and MotorStorm Apocalypse employ a light pre-pass variant of the deferred technique.
Other elements of the technical make-up of the Force Unleashed II engine have yet to be seen in UE3. For example, object-based motion blur is beautifully handled in the existing LucasArts game, and its camera-based implementation utilises the strengths of the PlayStation 3 architecture in producing an effect smoother and more pleasing than the equivalent on Xbox 360. Conversely, in many UE3 titles, camera-based motion blur actually uses fewer samples on the PS3 compared to the 360 version and while object-based blur is in the engine, implementation has been restricted. In creating TFUII, LucasArts put extensive effort into SPU usage, following the example set by Sony first party developers in offloading traditionally GPU-driven effects onto Cell's powerful satellite processors.
Another interesting element to consider is overall performance. In Digital Foundry's continuing analyses over at Eurogamer, we consistently see the Xbox 360 version of Unreal Engine 3 titles operating with a notably more consistent frame-rate than PlayStation 3 equivalents. Indeed, in our latest analysis of Epic's own Bulletstorm, we see a slight performance deficit on PS3 and some pared back effects, including the studio's excellent god-ray tech: implemented nicely on Xbox 360 but absent on PS3.
In contrast, The Force Unleashed II demonstrated that LucasArts was getting seriously good at matching performance levels between the two consoles using its in-house tech - the leap over what was seen in the first game was remarkable. While there was still a 360 advantage in terms of absolute number of frames generated per second, the PS3 release compensated with higher precision effects.
Anti-aliasing is another issue where LucasArts did some fine work, employing a perceptual, directional approach (DLAA) that brought some exemplary edge-smoothing to the game. It's a post-process effect just like morphological anti-aliasing (MLAA) and while it does have some artifacting issues, it's effective and innovative nonetheless. In contrast, we've only seen limited anti-aliasing implementations within Xbox 360 versions of Unreal Engine 3 titles, and to the best of our knowledge, none at all of note on PlayStation 3 (we won't include blur filters, like those seen in Army of Two: 40th Day).
Combine the excellent tech work on The Force Unleashed II with Lucas's intriguing experimental work on 60Hz frame-rate upscaling, and it's clear that there's some serious talent at the studio. The question now is whether we will see any of this advanced work appear in future LucasArts titles, while many must be wondering why the studio would opt for UE3 if its existing tech can produce such visually accomplished, unique results.
Undoubtedly, business plays a major part in the decision. Unreal Engine allows for relatively painless cross-platform development on PC, Xbox and 360, with the option there to develop for just about any platform at all that supports programmable pixel shaders (iOS, Android, Project Cafe etc). Its development tools are considered to be user-friendly, and the tech has powered some of the most commercially successful games of this generation. Obviously, fewer staff would be required if much of the technology side of things is being taken care of by the middleware, and the engine has proven its worth across a range of game genres - quite how the TFUII tech would scale across to other game styles will probably never be known.
Not only that, but LucasArts clearly has its eye on the future in inking a long term deal. As we begin to approach the arrival of the next generation of consoles, so another wave of R&D needs to kick off in order to transition across to the new hardware. A deal with Epic effectively insulates LucasArts from the costs of having to develop a brand new engine technology from the ground up. The recent GDC Samaritan demo wasn't just a vision of the future, it comes across almost like a pledge to the industry that buying into Unreal Engine makes you next-gen ready. It's no mistake that similar claims are being made by Crytek with its own CryEngine 3.
In the here and now, the market remains very much geared towards the current generation. PC, Xbox 360 and PlayStation 3 won't be superseded any time soon, and while it might be logical to expect Project Cafe to outstrip current gen performance, it would take a significant leap in GPU power to consider it a true next gen console; gut feeling suggests that Nintendo wouldn't be able to afford this if the make-up of its innovative new touchscreen controller is to be factored into a $350 product. And since when has Nintendo been concerned about beating the competition on specs any way?
As the current console generation matures, some seriously impressive technical work is being carried out – not just on bespoke engine tech, but with Unreal Engine 3 as well. While deferred rendering doesn't come with UE3 out of the box, that hasn't stopped its implementation being factored into selected games. For example, to the best of our knowledge, Danger Close's Medal of Honor is the first game using Unreal Engine 3 that shipped with light pre-pass deferred lighting, on top of a whole host of additional technologies that are not a part of Epic's standard package. Environmental destruction, particle effects and god-rays are using bespoke code as opposed to the existing middleware's components and the overall impression is of a game clearly divorced from the signature UE3 look and feel.
Epic's tech is also being used in new and different applications. The recent release of Mortal Kombat on PlayStation 3 and Xbox 360 demonstrates the engine managing to run at full 720p resolution while maintaining a 60Hz update, plus there's support for stereoscopic 3D on the PS3 too.
Going forward, exciting work is taking place with UE3 over at Irrational Games, where the core tech is being radically re-engineered. Deferred lighting is being introduced to the engine in addition to, as technical director Chris Kline puts it, "a proprietary per-pixel dynamic relighting scheme that allows characters and dynamic objects to receive global illumination."
On top of that the entire job processing pipeline is being changed in order to eke out more power from the multi-core set-up of modern PCs and consoles – and will hopefully serve to level the performance differences we've seen between Xbox 360 and PS3 Unreal Engine 3 titles. AI and animation also receive a radical refresh, while audio systems are beefed up with a 5.1 surround system with adjustable dynamic range and mixing on top of many other enhancements.
The whole topic of how UE3 has been adapted by enterprising developers is a topic worthy of a feature in its own right, but in the here and now the point is that although a shift from LucasArts across to the Epic tech may seem puzzling, the impressive efforts in technological innovation we've seen from the studio could be re-focused on making its UE3 titles truly remarkable...