Procedural content generation (preview)

Dawn Engine PCG (procedural content generation) covers two related tracks: a PolyTerrain-bound PCG pipeline already shipping inside the PolyTerrain Gem, and a planned general-purpose PCG Gem that will plug into the same buses for broader procedural workflows.

Maturity:

What problem it solves

Hand-sculpting every cliff, weight mask, and prop cluster does not scale to open worlds. PCG is intended to automate:

• Surface query → transform / filter → write-back for erosion-like and sculpt layers;
• Weight-channel driven material and vegetation masks;
• Deterministic instance placement (Patch and Mesh Projection modifiers);
• Reusable graph assets (.polypcggraph) that stay level-agnostic until run against a partition.

The long-term Gem keeps that workflow while adding a shared node/runtime substrate other systems (foliage, clutter, mission props) can extend without forking PolyTerrain.

Already available (PolyTerrain PCG)

If you only need mesh-terrain procedural edits today, enable PolyTerrain and its PCG subsystem (see PolyTerrain optional features). Capabilities already landable:

With PCG runtime execution off (default), editor authoring and bake behavior stay unchanged for projects that never touch graphs.

Planned: general-purpose PCG Gem

The open long-term item is an independent O3DE-style PCG Gem. Target integration rules already written down:

1. Same entry points — future Gem talks to PolyTerrain only through PolyPartitionPcgRequestBus and .polypcggraph data; no parallel write path into section meshes.
2. Determinism — seeds and outputs that affect bake must land in modifier parameters (hence ContentHash), not a hidden side channel.
3. Optional build / load — projects that never enable PCG must not pay runtime cost (Registry / subsystem gating, matching today’s PolyTerrain pattern).

Candidate expansions after the shared Gem lands (not committed dates):

• Broader node libraries (scattering, spline sampling, biome filters) beyond the PolyTerrain eight-node set;
• Cross-system outputs (Vegetation descriptors, World Streaming cell stamps, mission Prefab variants);
• Stronger editor interoperability with other GraphModel canvases where semantics allow.

How the PolyTerrain loop works today

.polypcggraph ──► Validate / topological execute
 │
 ├─ QuerySurface(ToSubPriority) ──► point cloud (+ weights)
 ├─ Offset / Noise / Slope / Weight filters
 └─ Write / SpawnPatch / SpawnMeshProjection
 │
 ▼
 Modifier params → Preview rebuild / Bake → Atom + PhysX

Best practice: Query and Write share the same Priority Layer / Sub-Priority, and Query must not be inclusive of the layer it writes to (avoids feedback loops).

Related systems

Status and next steps

• Use now: PolyTerrain optional features — PCG graph editor and buses for mesh-terrain procedural edits.
• Watch next: standalone PCG Gem announcement in a future release; this preview page will then grow into a full Quick start for engine-wide graphs.