This demo previews two of the new core technologies that will debut in Unreal Engine 5 that are described below.
According to the company, Nanite virtualized micropolygon geometry frees artists to create as much geometric detail as the eye can see. Nanite virtualized geometry means that film-quality source art comprising hundreds of millions or billions of polygons can be imported directly into Unreal Engine—anything from ZBrush sculpts to photogrammetry scans to CAD data. Nanite geometry is streamed and scaled in real time so there are no more polygon count budgets, polygon memory budgets, or draw count budgets; there is no need to bake details to normal maps or manually author LODs; and there is no loss in quality.
Lumen is a fully dynamic global Illumination solution that immediately reacts to scene and light changes. The system renders diffuse interreflection with infinite bounces and indirect specular reflections in huge, detailed environments, at scales ranging from kilometers to millimeters. Epic claims that artists and designers can create more dynamic scenes using Lumen, for example, changing the sun angle for time of day, turning on a flashlight, or blowing a hole in the ceiling, and indirect lighting will adapt accordingly.
Epic says that it is designing for forward compatibility, so that developers can get started with next-gen development now in UE4 and move projects to UE5 when ready. Epic will release Fortnite, built with UE4, on next-gen consoles at launch and, in keeping with the team’s commitment to prove out industry-leading features through internal production, migrate the game to UE5 in mid-2021.