SA PCG metadata reference

Attribute names are case-sensitive. Use Data-domain filters for whole paths/lots and element filters after sampling for individual points. PCG data tags are separate from metadata attributes; use Filter Data By Tag for them.

Streets and lots

Attribute	Type	Meaning
SA_SourceActor	String	Owning source actor name.
SA_LotIndex	Int	Lot order in the current source/result.
SA_LotEmpty	Bool	Effective lot config suppresses surfaces/spawns.
SA_LotArea	Float	XY polygon area in cm².
SA_LotSeed	Int	Stable per-lot seed token.
SA_LotSurfaceMaterial	Soft Object Path	Resolved visible/top lot material.
SA_LotZone	Name	Lot Zone actor, per-lot override, or default lot zone tag.
SA_IsExterior	Bool	Subdivided lot touches its source boundary.
SA_IntersectionNode	Int	Graph node index owning an intersection.
SA_CorridorIndex	Int	Resolved road corridor index.
SA_RoadSide	Name	Left or Right.
SA_CrossingIndex	Int	Road-mouth crossing order.
SA_RoadWidth	Float	Full width at the crossing.
SA_ConfigIndex	Int	Streets Street Config index.
SA_DistanceAlongSpline	Float	Cumulative world distance on centerlines or effective splines.
SA_StreetConfigIndex	Int	Street Config that built the road a lot edge follows.
SA_LotPerimeter	Float	Boundary length in cm.
SA_LotWidth	Float	Frontage width of the lot, in cm.
SA_LotDepth	Float	Depth back from the frontage, in cm.
SA_LotForward	Vector	Direction the lot faces, away from its street.
SA_LotFrontageCount	Int	How many streets the lot fronts onto.
SA_IsCornerLot	Bool	Lot fronts two or more streets that meet at a corner.
SA_StreetFacing	Bool	Per boundary point: this edge runs along a street.
SA_AtIntersection	Bool	Per boundary point: this point sits at an intersection.
SA_TouchesBoundary	Bool	Per point: the edge starting here lies on the source boundary. On Gap Outlines this marks an alley mouth; on alley sides it is false.
SA_CutGap	Float	Alley width on Cut Lines and Gap Outlines. 0 when there is no gap.
SA_CutPass	Int	Which subdivision pass produced this cut line.
SA_JunctionDegree	Int	How many cut lines meet at a Cut Junction point.
SA_JunctionOnBoundary	Bool	The Cut Junction sits on the lot edge rather than inside it.
SA_IslandArea	Double	Plan-view area of a boundary island, after facet thinning.

Lot shape metrics - SA_LotWidth, SA_LotDepth, SA_LotForward, SA_LotFrontageCount, SA_IsCornerLot - are what make "put shops on corner lots and houses elsewhere" a one-node filter.

Effective spline attributes

SA Get Spline can write:

Attribute	Type	Meaning
SA_ActorType	Name	Wall, Building, Curve, or supported source kind.
SA_Preset	Name	Effective DataTable row/preset name when available.
SA_Seed	Int	Resolved actor seed.
SA_Baked	Bool	Source actor bake state.
SA_SplineClosed	Bool	Effective path is closed.
SA_MirrorMode	Name	Resolved mirror/bisect mode.
SA_StackIndex	Int	Wall depth: root 0, child 1, and so on.
SA_StackOffset	Vector	Effective cumulative connected-layer offset.
SA_WallHeight	Float	Effective wall/profile height.
SA_NumFloors	Int	Effective floor count.
SA_SegmentIndex	Int	Segment index for per-control-point/segment semantics.
SA_SegmentLength	Float	Segment world length.
SA_SegmentDirection	Vector	World direction.
SA_CornerAngle	Float	Turn angle at the point.
SA_NormalizedDistance	Float	Distance along path normalized 0–1.

Facade frames

Attribute	Type	Meaning
SA_SourceActor / SA_SourceType / SA_Preset	String/Name/Name	Source identity and resolved type/preset.
SA_WallId / SA_ParentWallId	Name	Building hierarchy IDs.
SA_PathIndex / SA_StackIndex	Int	Effective path and connected-layer depth.
SA_StackOffset	Vector	Layer offset.
SA_WallSide / SA_FacadeFace	Name	Spline-relative side and semantic exterior/interior face.
SA_SegmentIndex	Int	Owning wall segment.
SA_FloorIndex / SA_LocalFloorIndex	Int	Global stack floor and floor within the current preset.
SA_DistanceAlongWall	Double	Cell position along the wall run.
SA_NormalizedU / SA_NormalizedV	Double	Normalized position over the resolved face.
SA_NormalizedFloorV	Double	Normalized vertical position within the current floor.
SA_CellSize	Vector	Fitted cell size in centimeters.

Floor and roof samples

Attribute	Type	Meaning
SA_SourceActor	String	Source Wall, Building, or Curve.
SA_SurfaceType	Name	Floor or Roof.
SA_SurfaceFloor / SA_SurfaceRoof	Bool	Convenient type flags.
SA_FloorIndex	Int	Sampled floor index.
SA_IsTopFloor	Bool	Sample belongs to the uppermost resolved floor.
SA_Preset	Name	Source preset.
SA_Material	Soft Object Path	Sampled surface material.
SA_Slope	Float	Surface slope in degrees.

Polygon, prop, and spawn output

Attribute	Type	Meaning
SA_Offset	Float	Signed polygon offset applied.
SA_IslandIndex	Int	Polygon Merge island order.
SA_Mesh	Soft Object Path	Mesh selected/generated for Static Mesh Spawner By Attribute.
SA_Actor	Soft Object Path	Actor class selected for Spawn Actor By Attribute.
SA_SpawnedActor	Soft Object Path	PCG-managed actor reference emitted in Components/Actors modes.
SA_PresetTags	Name Array	Exact applicable Building/Wall Preset tags on generated piece, Dynamic Mesh, or actor-reference output.
SA_DistanceToSpline	Double	Horizontal or 3D distance computed by SA Orient To Spline.
SA_IsHole	Bool	This closed shape is the hole of a larger shape, not a shape of its own. Written on every output of the nodes that can emit holes, false on outlines, so a filter always finds it.
SA_PointCount	Int	How many input points belong to a shape traced by SA Polygon From Points.
SA_PresetRow	Name	Custom Piece Preset row chosen by SA Set Custom Piece.
SA_PresetTable	Soft Object Path	The DataTable that row lives in.
SA_ApplyToAll	Bool	This piece point spreads to every run in reach instead of only the nearest.
SA_ActorClass	Soft Object Path	Actor class resolved for a spawned piece.
SA_PCGManaged	Tag	Actor tag on everything PCG spawns for SA. Present so SA's own getters can ignore their output and never feed it back in - do not filter on it by hand.

Attribute inheritance through transforms

Nodes that reshape lots pass attributes along rather than starting fresh, so a filter written against SA Get Lots still works after a subdivision.

SA Subdivide Lots emits its own SA_LotIndex, SA_LotArea, SA_LotSeed, and SA_IsExterior describing each sub-lot, and these override the parent's values of the same name. Every other Data-domain attribute of the parent lot rides through untouched - SA_LotZone, SA_StreetConfigIndex, SA_RoadWidth, SA_LotSurfaceMaterial, SA_SourceActor, and anything an upstream Add Attribute put there.

One consequence to keep in mind: inherited shape metrics still describe the parent lot. After a subdivision, SA_LotWidth, SA_LotDepth, SA_LotForward, SA_LotFrontageCount, and SA_IsCornerLot are the block's, not the sub-lot's.

SA Polygon Merge and SA Polygon Offset keep an attribute only when every input agrees on its value. Merging lots from two different Streets Networks drops SA_SourceActor; merging lots at all drops SA_LotIndex and SA_LotArea, because the island has no single answer.

Preset tags and filtering

SA_PresetTags preserves the authored Name values and their component-level precision:

• a standalone Wall piece carries its Wall Preset tags;
• a Building piece carries the Building Preset tags plus only the Wall Preset tags that produced that component;
• a Building actor-reference point carries only the Building Preset tags;
• a Wall actor-reference point carries only the Wall Preset tags;
• Curve output carries an empty array because Curve presets do not define Preset Tags.

In Data output, static-piece points store the array on each point. Each Dynamic Mesh stores it on the Data domain. Components/Actors reference points also expose the top-level array.

To keep individual pieces with a tag such as BaseFloor, use stock Array Contains on SA_PresetTags, then feed its result to Attribute Filter. To keep or branch a complete generated output by a top-level tag such as Small, use Filter Data By Tag. Dynamic Mesh outputs also carry their precise component tags as PCG data tags.

Do not rename these attributes in the middle of a shared graph without updating every filter and stock spawner. For a stable studio graph, wrap common SA branches in PCG subgraphs and expose only high-level parameters.