PCG — Procedural Content Generation¶

PCG is Unreal's native, graph-driven procedural content system. Introduced in 5.2, hardened in 5.3, fully production in UE 5.7 with Biomes and Subdivision shipping as separate plugins. It replaces hand-painted Foliage, custom Houdini-Engine pipelines for level dressing, and most spline-based scattering tools.

Plugins to enable¶

Plugin	Role
Procedural Content Generation Framework	Core graph system, nodes, runtime
PCG Geometry Script Interop	Generate / sample meshes from PCG
PCG Examples	Reference graphs you can dissect
PCG Biomes	Layered biome blending
PCG Subdivision	Recursive partitioning operators

Enable under Edit → Plugins → search "PCG", restart.

Mental model¶

graph LR
  V[PCGVolume actor] -->|defines bounds| G[PCGGraph asset]
  G -->|samplers| P[Point data]
  P -->|filters / ops| P2[Filtered points]
  P2 -->|spawners| O[Instanced meshes, actors, splines]
  G -.->|debug overlay| E[Editor viewport]

Graphs are .uasset files you edit in a node graph.
Points are the universal data type — a position, rotation, scale, density, and attribute bag.
Bounds come from a PCGVolume actor or any actor with a PCGComponent.
Generation is triggered manually in the editor, on actor spawn, or per World Partition cell at runtime.

Pages¶

Graph basics — anatomy of a PCGGraph
Samplers and spawners — how to turn bounds into populated meshes
Volumes and bounds — how PCGVolume interacts with World Partition
Biomes — layered density-based blending
World Partition — per-cell PCG generation at runtime

Why use PCG over Foliage / Procedural Foliage Volume¶

Concern	Foliage	PCG
Authoring	Paint each species	Graph-driven, parametric
Re-runnability	Manual repaint	Re-runs on world change
Multi-layer rules (e.g. "trees only on slopes < 30° not under power lines")	Hard	Trivial
Runtime generation	No	Yes, per WP cell
Diff / version control	Painted state is huge data	Graph is a small uasset
AI / scripting integration	None	Full Python + Blueprint API

Typical first graph¶

The "scatter trees on a heightfield within a volume" graph fits in 6 nodes:

SurfaceSampler (Landscape) → Density Filter (slope < 30°) → Random Selection
  → Static Mesh Spawner (Trees Asset Set) → Output

Add a Difference node fed by a road spline to carve out a no-spawn zone, and you've replaced an afternoon of manual placement with a re-runnable rule.

What ships in the box¶

Folder	Contents
`Engine/Plugins/PCG/Content/Examples/`	Five reference graphs (forest, grass, urban, biome, debug)
`Engine/Plugins/PCG/Content/Blueprints/`	Reusable subgraph BPs
`Engine/Plugins/PCG/Content/Misc/`	Test sets, point data, splines