PCG system selector

Choose the generation mode

Need	Mode	Cost/constraint
Small bounded authoring tool	Non-partitioned editor generation	simplest; one component domain
Large persistent generated area	Partitioned editor generation	grid cells integrate with streaming
Multiple detail scales	Hierarchical generation	shared large-grid work feeds smaller grids
Viewer/source-dependent transient content	Runtime generation	scheduler, memory, cleanup, and pop budget

PCG generation modes are not visual-quality settings. Select them from domain size, update frequency, output lifetime, and streaming requirements.

Bake versus runtime

Prefer editor-generated/baked output when content needs:

• manual art review and source-control visibility;
• HLOD or static baked lighting;
• persistent instance data;
• collision, navigation, ray tracing, or distance-field participation;
• deterministic cook output without runtime generation stalls.

Use runtime generation when player position, runtime terrain/state, or effectively unbounded content makes baking impractical. Runtime generation must define generation sources, radii, cleanup radii, scheduling policy, memory/caching, and what happens when generation falls behind.

Partitioned versus hierarchical

• Partitioned generation divides one component's domain into PCG grid cells.
• Hierarchical generation lets branches execute at different grid sizes through Grid Size nodes.
• Put broad, reusable calculations on larger grids and dense local detail on smaller grids.
• Data produced on a larger hierarchical grid is cached for smaller-grid execution.
• Choose cell/grid size from content size and cost, not one universal number.

CPU versus GPU

Stay on CPU for small point counts, frequent CPU consumers, Actor spawning, unsupported nodes, or when transfer overhead dominates. Evaluate GPU when long connected GPU-capable regions process enough points to amortize upload/download and compute-graph setup.

PCG GPU Processing is Beta. GPU procedural instancing is a narrower Experimental output path with major persistence and feature limitations. See gpu-processing.md.

Related skills

• Route World Partition/Data Layer/HLOD ownership to $unreal-world-partition.
• Route spline construction and spline meshes to $unreal-splines.
• Route asset definitions/soft loading to the future unreal-data-assets-tables skill.
• Route final bottleneck work to $unreal-insights-profiling when available.