Unreal Engine 5.5’s experimental MegaLights feature, unveiled at Unreal Fest, enables developers to use numerous shadow-casting lights without significant performance degradation. This update allows for 1,000 light sources, movable and dynamic shadows, and realistic area shadows. Wyeth Johnson, Epic Games’ senior director, likened MegaLights’ impact to Nanite and Lumen. The feature enhances game development and shadow handling. Demoed on a PlayStation 5, MegaLights won’t appear in games for 2-3 years due to development and pipeline timelines, but promises significant visual improvements.
Last week, the Unreal Fest in Seattle introduced MegaLights, an experimental feature in Unreal Engine 5.5. It enables developers to work with significantly more shadow-casting lights without substantial performance degradation.
The update brings orders of magnitude more lights. They are movable and dynamic, with realistic area shadows, and can light volumetric fog. The update can use 1,000 light sources—not quite a mega, but a helluva lot of light sources.
“Like Nanite did for triangles or Lumen for global illumination, MegaLights removes limitation in a whole new category: direct lighting and shadows,” said Wyeth Johnson, senior director of product strategy for Unreal Engine at Epic Games.
Being able to use many lights significantly benefits game development, as is illustrated in the video. And it also enhances shadow handling, as MegaLights features movable and dynamic shadows. The marketplace scene in the video showcases this, transforming from a polished appearance to a more nuanced and detailed environment when realistic shadows are enabled for each visible light source. Game developers and artists want to use lots of lights, but they typically have to limit the number to get them to run on average hardware.
And as if to make a point about how much GPU power is needed, the MegaLights live demo was run on a PlayStation 5 console.
However, it takes time to get new software running bug-free and then get the results through a development pipeline, so we won’t see these effects in a game for probably two to three years—but it will be well worth waiting for.