Compile/VR Gyro
Recently, Epic Games released the latest version of its next-generation game engine, Unreal Engine 5, which will be available to all developers starting this week.
The new version brings improvements in many ways, the most prominent of which are Lumen (Dynamic Global Illumination) and Nanite (Virtual Geometry System), the arrival of which promises to usher in a new era of game development, making it easier for developers to create games with extremely high-quality and realistic lighting.
Unfortunately, the company says these two features aren't ready for VR developers.
Nanite
Nanite is epic's so-called "virtual geometry" system, which radically improves the geometric details in the game scene.
In the past, developers would create high-quality 3D models as a "master" reference and simplify their geometry (thereby reducing detail and complexity) before introducing them to game engines. The same model will often get multiple versions with different details, and the "pop" between these versions depends on the distance between the game lens and the model (the so-called "level of detail" or "LOD"). This allows the game to display higher quality at greater distances while preserving performance when using lower quality models.
Nanite is essentially like a continuous LOD system, extracting detail from the original "master" model, rather than relying on pre-built models that reduce detail. In each frame, the system references the master model and extracts the maximum level of detail required for a given camera distance. Not only does this eliminate the need to create discrete LOD models, but it also means that the model can have a greater range of details, allowing players to see incredible details and perform deep restoration.
Image source: roadtovr
Lumen
At the same time, Lumen, Unreal Engine 5's new lighting system, greatly simplifies the production of game lighting with global illumination.
Realistic lighting can be computationally expensive, and without Lumen, many games use a combination of lighting techniques to achieve the effect they want while maintaining game performance. A given scene might simulate realistic lighting using preset static lighting (which does not interact with the rest of the scene), a small number of real-time lights (casting shadows on specific objects in the scene), and various "screen space" effects.
Lumen unifies lighting into a method called global illumination, which aims to turn every light in a scene—even the sun—into a real-time light that interacts with other lights and scenes. This includes realistically reflected light, which propagates colors throughout the scene based on the color of the object the light hits. For example, when white sunlight hits a white room with a red floor, it projects some red light onto the wall as it bounces off the red floor, and this reflective lighting is an important part of simulating real lighting.
There is no specific plan for VR support for the two major functions
In fact, both Nanite and Lumen can greatly enhance the immersion of VR thanks to their ability to greatly enhance the geometric detail of objects (which is especially important for 3D stereoscopic graphics in VR headsets) and the ability to create more realistic and interactive real-time lighting.
Unfortunately, Epic says neither Nanite nor Lumen in UE5 is ready for VR.
"While we don't have specific time plans to share Lumen and Nanite's support for VR experiences at this time, we're exploring how we can bring these UE5 features to other platforms." The company told foreign media.
However, Epic also emphasizes that this does not mean that VR developers can use UE5.
"VR developers can take advantage of most of Unreal Engine 5's production tools and features, such as new UI, new suite of modeling tools, Control Rig, MetaSounds, and creator tools like World Partition for large open environments."
Image source: Network
VR lacks performance support, and UE needs to be optimized
Both Nanite and Lumen were able to create incredible game scenes, but from a performance standpoint, they weren't completely "free."
"Although the advantages of (Nanite) can be game-changing, there are still limitations in practice. For example, for any combination of content and hardware, you should carefully measure the number of instances, triangles per mesh, material complexity, output resolution, and performance. Nanite will also continue to expand its capabilities and improve performance in future versions of Unreal Engine. The company told developers.
In addition, in terms of host hardware adaptation, Lumen's large outdoor scene frame rate design only supports 60 frames, and the indoor scene frame rate is only 30 frames, which is far from the minimum 90 frame rate configuration of most PC VR headsets. This may mean that the introduction of these capabilities into VR will eventually lack performance support.
Meanwhile, on the latest console hardware, Lumen's large outdoor scenes have a frame rate of only 60 frames and indoor scenes at a frame rate of only 30 frames. This is a far cry from the minimum 90 frame rate for most PC VR headsets. Because Quest 2 is not configured as well as the latest hosts, it is unlikely that it will meet these needs. This could mean that bringing these features to VR will ultimately lack performance support.
Since VR requires stereoscopic rendering (usually higher resolution), flat screen rendering does not require such high performance requirements in the same scene. Things like single-pass stereoscopic and center point rendering, while there are assistants that improve their efficiency, may not yet work with tools like Nanite and Lumen.
Therefore, optimization and more powerful hardware may be required before these capabilities can be brought into the VR experience. From Epic's perspective, Unreal Engine has only a small percentage of VR developers compared to Unity, and the vast majority of VR games today are based on the Unity engine. Especially as Meta's Quest 2 becomes the most popular target platform for developers (it's underpowered compared to consoles and PCs), optimizing Nanite and Lumen's VR capabilities seems to be at a very low priority for Epic.
Source: roadtovr