You may know Dmitry Karpukhin as the creator of the Sky Creator plug-in, as well as for his various experimental projects, which we’ve featured on 80 Level multiple times. Now, the developer experimented with Unreal Engine’s Global Illumination using the Plugin item, resulting in a custom GI implementation.
This is still a very rough and unoptimized prototype, but interestingly, it’s already performing faster than Lumen, though naturally, it’s much less accurate. In this early stage, Dmitry is simply imitating large-scale ambient occlusion using Global SDFs, with no sunlight bounces implemented yet.
Dmitry also shared a few observations: for example, it doesn’t seem possible to cast custom shadows on volumetric fog because that part of the engine is hard-coded. There’s also no hook available for custom reflections, although it might be possible to leverage the roughness buffer within the same GI pass. Additionally, the Material AO buffer remains inactive if Allow Static Lighting is enabled. This buffer appears well-suited for custom ambient occlusion, as it automatically blocks reflections and skylight influence on surfaces.
You can learn about this approach here and check out more experiments with this custom GI plug-in:
