Crytek details recently shown video with ray tracing technology
In a blog post, Crytek explained a demo video published in March in which the game company demonstrated its own version of ray tracing using CryEngine 5.5. The engine uses, among other things, voxel cone tracing.
Crytek reports that the video called Neon Noir has a 1080p resolution and runs at 30 frames per second. If necessary, the performance can be boosted by limiting the resolution of the reflections, whereby, according to the company, the loss of quality is still limited. For example, it is possible to run the video in a mode where the reflection resolution is halved at 1440p with more than 40fps. The company says that this video does not yet take advantage of performance increases that are possible through modern APIs, such as DirectX 12 or Vulkan. The ray tracing technology shown will be further optimized so that the capabilities of these APIs and the latest video cards can also be used.
It was already known that the scenes from the video were rendered on a Vega 56 GPU from AMD; so no Nvidia RTX GPU was used. Crytek argues that the ability to flexibly and dynamically switch between “expensive” mesh tracing and “cheap” voxel tracing is an important explanation for why the ray tracing shown can run efficiently on non-RTX hardware. In addition, existing techniques are used, such as the screen space ambient occlusion developed by Crytek itself. “These two points help to minimize the amount of meshray tracing and mean we get good performance on mainstream GPUs,” the game company reports.
Nvidia RTX video cards have not been completely made redundant by the implementation of Crytek. The studio says that when they run the demo on a GTX 1080, they typically run reflections and refractions at half the resolution. With RTX GPUs, that would ‘probably’ allow full screen with a 4k resolution. In addition, RTX GPUs should allow for the addition of more dynamic elements. In short, RTX does not bring new features to the CryEngine, but it does lead to better performance and more details, according to Crytek.
Incidentally, the current implementation of ray tracing, as visible in the video, is only applied for reflections and light refractions. Crytek seems to indicate that applying ray tracing for ambient occlusion and creating soft shadows is out of the question for now. This is partly due to Crytek’s finding that shadow maps already work quite well in most scenes in games and that the current voxel-based ambient occlusion already performs well. Currently, ray tracing is only used for highly reflective surfaces.
With the ray tracing technology in the video, Crytek has built on a system for calculating lighting effects that already used a lot of ray tracing, namely voxel cone tracing. As a result, according to Crytek, it was not necessary to build a new lighting system from scratch. In fact, the video combines the data from voxels and ray tracing to deliver the best performance without creating visual artifacts.