PhysicsFixedSettingsComponent

A singleton component that holds fixed physics settings baked at startup. Values come from Physics settings and LOD and the Unity layer collision matrix; they are treated as fixed for the session after bootstrap.

Internal systems read this component for caps, LOD tiers, pair-check toggles, layer filtering, and spatial-map bounds. Custom code can read it too — for example to respect MaxEntitiesCount or query whether two layers collide.

Component fields

Field	Type	Description
`BlobRef`	`BlobAssetReference<PhysicsSettingsBlobAsset>`	Persistent reference to the packed settings blob
`SpacialMap`	`SpacialMap`	Grid definition and cell dimensions for the spatial map

Access blob data with fixedSettings.BlobRef.Value (or ref fixedSettings.BlobRef.Value when you need a ref).

SpacialMap

Set from SpacialMapAuthoring at bootstrap. Holds the Grid3D definition and GridSize in cells. Collision and map systems use it to convert world positions to cell indices.

See Spatial map.

PhysicsSettingsBlobAsset

The blob is created once in LittlePhysicsBootstrapSystem and stored in BlobRef.

Field	Type	Source	Role
`MaxEntitiesCount`	`int`	`PhysicsSettingsAuthoring.MaxEntitiesCount`	Upper bound on bodies imported each frame; excess entities are ignored
`LayersMaps`	`BlobArray<int>`	Unity `Physics.GetIgnoreLayerCollision`	Per-layer bitmask of which other layers can collide (32 entries)
`LodData`	`BlobArray<PhysicsLodData>`	LOD list on `PhysicsSettingsAuthoring`	Distance/vision tiers and per–time-scale capacity limits
`CheckSettings`	`CollisionCheckSettings`	`PhysicsSettingsAuthoring.CollisionCheckSettings`	Enables dynamic-vs-static and dynamic-vs-dynamic pair collection
`ShouldDebug`	`bool`	`PhysicsSettingsAuthoring.ShouldDebug`	When true, bootstrap creates debug capture entities

CollisionCheckSettings

Field	Default	Description
`CheckDynamicVsStatic`	`true`	Include dynamic–static pairs in broad phase
`CheckDynamicVsDynamic`	`true`	Include dynamic–dynamic pairs in broad phase

PhysicsLodData

Each LOD tier in LodData defines a Range, optional VisionAngle, and int3 capacity fields (DynamicsInCells, StaticInCells, CellPerEntity, PairPerEntity, CollisionPerEntity) resolved at time scales ×1, ×2, and ×4. Import and collision systems pick the active tier per body to cap spatial-map and pairwise work.

See Physics settings and LOD and How it works — LOD.

Layer collision helper

Use the extension on PhysicsFixedSettingsComponent to test the baked layer matrix:

var fixedSettings = SystemAPI.GetSingleton<PhysicsFixedSettingsComponent>();

if (fixedSettings.IsColliding(bodyLayer, otherLayer))
{
    // layers are allowed to interact
}

This reads LayersMaps[layer1] and checks the bit for layer2.

Air friction, push-out tuning, and substeps live on PhysicsVariableSettingsComponent, not here. SpacialMap and the settings blob are fixed for the session after bootstrap.

Physics settings and LOD — authoring setup for blob fields and LOD tiers
PhysicsVariableSettingsComponent — per-tick environment and substep settings
SimulationDataComponent — ActiveBodiesCount capped by MaxEntitiesCount
Spatial map — how cells and maps use SpacialMap