Nanite Virtualized Geometry Overview
- Virtualized geometry system; internal mesh format and rendering technology; pixel scale detail and high object counts; "does work on only the detail that is visible on-screen"; highly compressed; fine-grained streaming with automatic LOD.
- Benefits: orders of magnitude more geometry; "Frame budgets are no longer constrained by polycounts, draw calls, and mesh memory usage"; import film-quality art; high-poly detail rather than baking into normal maps; automatic LOD; quality loss rare. Practical limits remain (instance counts, triangles per mesh, material complexity, output resolution) – measure.
- Nanite meshes are still triangle meshes; flag on mesh; close enough draws original triangles; multiple UVs, vertex colors; virtual textures not required but highly recommended.
- How: "During import, meshes are analyzed and broken down into hierarchical clusters of triangle groups." "During rendering, clusters are swapped on the fly at varying levels of detail based on the camera view and connect perfectly without cracks to neighboring clusters within the same object. Data is streamed in on demand ... Nanite runs in its own rendering pass that completely bypasses traditional draw calls." SSD recommended.
- Should be enabled wherever possible; good candidates: many or very small triangles, many instances, major occluders, casts shadows with VSM. Exception: sky sphere.
- Disable Generate Lightmap UVs if not using baked lighting.
- Features: static meshes (no LODs, full Lumen & VSM support), skeletal meshes (one draw call, VSM, animation LODs), landscapes, foliage, splines, static displacement, tessellation.
- Limits: max 16 million instances (streamed-in instances count); no per-vertex tangents (derived in pixel shader); deformation: rigid transforms; WPO supported but limited (clamp displacement); morph targets not supported; materials Opaque and Masked only; custom expressions may artifact (no analytic derivatives). Not supported: Min Screen Radius, distance culling, Forward Rendering, VR stereo, MSAA, Lighting Channels; ray tracing uses Fallback Mesh (experimental native r.RayTracing.Nanite.Mode 1).
- Platforms: current consoles, desktop DX12 SM6.