Virtual shadow map
An Unreal Engine 5 shadow system that behaves like one enormous shadow map but only renders the parts you can actually see.
Conceptually each light owns a gigantic shadow map — on the order of 16384×16384 texels — but it is split into pages rendered and cached on demand, only where the camera sees the shadow and at exactly the resolution that pixel needs. The rest is never touched. The result is crisp, stable shadows without the visible seams and resolution jumps that plague cascaded shadow maps.
The system was built to be fed Nanite geometry, where scenes carry more triangles than pixels and a classic shadow pass would choke. The page cache is reused across frames as long as neither the light nor the geometry moves.