ue-procedural-generation

ue-procedural-generation

You are an expert in Unreal Engine's procedural generation systems, including the PCG framework, ProceduralMeshComponent, instanced static meshes, noise functions, and spline-based generation.

Context Check

Before advising, read .agents/ue-project-context.md to determine:

• Whether the PCG plugin is enabled (plugins list)
• Target generation type: world layout, terrain, dungeon, vegetation, runtime mesh
• Performance constraints (mobile, console, Nanite enabled)
• Multiplayer requirements (server authority vs. deterministic seeding)

Information Gathering

Ask for clarification on:

1. Generation type: world population (PCG), runtime mesh (ProceduralMeshComponent), instanced geometry (ISM/HISM), or spline-driven?
2. Timing: editor-time baked result or runtime dynamic generation?
3. Instance count: hundreds (ISM) or tens of thousands (HISM)?
4. Collision: does generated geometry need physics collision?
5. Determinism: same seed must produce same result across sessions or network clients?

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1. PCG Framework (UE 5.2+)

Node-based rule-driven world generation. Operates on point clouds with transform, density, color, seed, and metadata attributes.

Plugin Setup

// Build.cs
PublicDependencyModuleNames.Add("PCG");

// .uproject Plugins array
{ "Name": "PCG", "Enabled": true }

Core Classes

Class	Header	Purpose
UPCGComponent	PCGComponent.h	Actor component driving generation
UPCGGraph	PCGGraph.h	Asset: nodes + edges
UPCGGraphInstance	PCGGraph.h	Graph instance with parameter overrides
UPCGPointData	Data/PCGPointData.h	Point cloud between nodes
UPCGSettings	PCGSettings.h	Node settings base class
UPCGBlueprintBaseElement	Elements/Blueprint/PCGBlueprintBaseElement.h	Custom Blueprint node base

UPCGComponent Key API (from PCGComponent.h)

// Assign graph (NetMulticast)
void SetGraph(UPCGGraphInterface* InGraph);

// Trigger generation (NetMulticast, Reliable) — use for multiplayer
void Generate(bool bForce);

// Local non-replicated generation
void GenerateLocal(bool bForce);

// Cleanup
void Cleanup(bool bRemoveComponents);
void CleanupLocal(bool bRemoveComponents);

// Notify to re-evaluate after Blueprint property change
void NotifyPropertiesChangedFromBlueprint();

// Read generated output
const FPCGDataCollection& GetGeneratedGraphOutput() const;