World Streaming baking

Baking turns authored Prefabs and WorldConfig into per-cell Spawnables and a runtime Manifest. Trigger bake from the partition view or from editor automation.

Product chain

Shard Prefabs + WorldConfig
 │
 ▼
PrefabProcessor → cell Spawnables + fragments
 │
.wsworld (single aggregation key)
 │
 ▼
Manifest Aggregator Builder
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 ├── .wsmanifest
 ├── optional .wschunk
 └── HLOD assets

Before bake, the editor validates with ValidateWorldDescriptor / ValidateManifest.

Trigger bake

Action	Scope
Bake World / `BakeWorld()`	Save all dirty shards + root → validate → Asset Processor rebuild; returns `BakeReport` (`m_ok`, `m_shardsSaved`, `m_cellCount`, `m_warnings`)
Bake Region / `BakeRegion(minD, maxD)`	Save only dirty shards overlapping the box; aggregator still runs for the whole world (incremental convergence)
Bake Grid Level / `BakeGridLevel(level)`	Save only the specified grid (`0xFF` = all)

Always Save Dirty Cell Shards (or let Bake World do it) before expecting fresh products. Panel entry: Tools → World Streaming → Bake World Streaming.

Manifest highlights

The .wsmanifest describes cell layout, dependencies, HLOD layers, and contentHash (used by multiplayer handshake). Memory estimates use a lightweight per-entity floor of 4096 bytes unless real asset sizes are enabled.

Manifest chunking

In .wsworld, when m_chunkSize > 0 and cell count exceeds m_chunkCellThreshold, bake emits a root Manifest plus .wschunk files for lazy metadata. Pair with runtime ChunkEvictionCooldownSeconds. Default m_chunkSize = 0 means no chunking.

Server shard index

.wsworld m_shardSize > 0 writes a server ownership index for multi-authority dedicated servers. Default 0 = single authority. This is unrelated to editor collaboration shards. Runtime ownership: Multiplayer.

Bake Settings Registry keys

Under /Dawn Engine/WorldStreaming/Bake/:

Key	Default	Description
`HlodWorkerThreads`	≤1 (serial)	Deterministic parallel HLOD workers; products match serial byte-for-byte
`AssignCellGenerations`	`false`	Assign `m_generation` from content digests
`MergeMultiSourceCells`	`false`	Merge multi-source cells; default off = duplicate CellId fails

With these off, products and contentHash stay byte-identical to an unconfigured bake. Turning keys on changes the hash.

Baker opt-in switches

Switch	Default	Effect
`m_autoGridLevelFromBounds`	off	Choose grid from world AABB
`m_clusterTransformHierarchy`	off	Transform subtree follows root cell
`m_resolveRealAssetSizes`	off	Memory estimates use real product bytes (hash becomes platform-sensitive)
`m_patchCrossCellHardRefs`	off	Record DependentLoad hard-ref repair table
`m_auditTwoTierActivation`	off	Two-tier activation audit (report-only)

Determinism and Golden Manifest

Bake is intended to be deterministic for CI. The Golden Manifest fixture lives at Gems/WorldStreaming/Code/Tests/Assets/GoldenManifest.wsmanifest. Format changes require regenerating it with WS_UPDATE_GOLDEN_MANIFEST=1.

GPU octahedral pre-bake

For HLOD policy GpuOctahedralImpostor (id 4):

In the partition view, run Bake GPU Octahedral Impostors (or BakeGpuOctahedralImpostors; optionally check IsGpuCaptureAvailable first).
Then run Bake World Streaming (missing atlas falls back to policy 3).
Optionally CaptureOctahedralImpostorScreenshots(outputDir) for inspection.

Details: HLOD.

Next steps

Runtime streaming: load the Manifest and drive sources.
Configuration and debugging: bake keys in the full Registry table.
Scripting: BakeWorld / BakeRegion / BakeGridLevel from Python.