Using PCG Generation Modes
- Generation modes split a PCG Component's generation domain into a grid, each cell with its own local PCG component; large grid for prominent meshes (trees, boulders), small grid for details (grass, flowers, stones). Four modes: Non-partitioned (default), Partitioned, Hierarchical, Runtime.
- Partitioned: meshes generated across a user-defined grid (Partition Grid Size on PCGWorldActor); data split per cell, easier to stream with World Partition and Level Instancing. Non-partitioned can cause performance issues over large areas.
- Hierarchical Generation: multiple scales; Graph Settings "Use Hierarchical Generation" + HiGen Default Grid Size; Grid Size node placed before sampler nodes sets grid for downstream data. Requires partitioned components. Large meshes (fewer) on larger grids, smaller numerous meshes on smaller grids. Data generated on a larger grid is available as cached data to smaller grids — cascades larger→smaller, never smaller→larger; node with inputs from multiple grid sizes outputs at smallest. Unbounded grid size executes once (e.g. expensive Mesh Sampler instead of once per cell). Subgraphs use parent/input grid size. Pitfall: duplicate point data when passing larger→smaller grid; remove with Cull Points Outside Actor Bounds.
- Runtime Generation: generates and cleans up dynamically near PCG Generation Sources (editor viewport if enabled on PCGWorldActor, player controllers, World Partition streaming sources, PCG Generation Source Components); available in editor, PIE, standalone; "most effective when paired with Hierarchical Generation". Generation Radii per grid size in graph settings; Cleanup Radius Multiplier; radii should increase with grid size (avoid small grids with larger radius). Scheduling policies (default: distance and view direction); 5.5 HiGen Grid Size Exponential increased Direction Weight importance. Use Frustum Culling with Generate/Cleanup Bounds Modifiers. Enable via Generation Trigger = Generate at Runtime. Console: pcg.RuntimeGeneration.Enable, pcg.RuntimeGeneration.EnableDebugging.