Project settings

Edit → Project Settings → Plugins → Spline Architect Settings holds the project-wide defaults. A value set on an actor always wins over these.

Settings

Control	What it does
Corner Angle Increment	Default rounding in degrees for reusable baked corner variants.
Default Bends Resolution	Arc sample distance for floor boundaries and curved corners.
Default Wall Preset	Inline setup assigned to newly spawned Wall actors before a row is chosen.
Default Baked Mobility	Initial Static, Stationary, or Movable mobility.
Default Bake Method	Initial Components, Instanced, or Hierarchical Instanced method.
On Level Save Action	Nothing, Rebake Unbaked, Rebake All, or Unbake All. Nothing is the safest team default because it avoids a large implicit save-time mutation.
Auto Normalize Actor Scale	Applies non-unit actor scale to spline points while preserving world shape, then resets the actor to 1,1,1.

Some settings are remembered per user, not here

The Pivot Tool's and Lightmap Tool's Overwrite Existing, the Delete Original Actors choices in the Convert, Collapse to Mesh, and Convert to Blueprint dialogs, the Preset Library's view mode, category tab, and favorites filter, the Streets Mode Node Merge Radius and Subdivide recipe, and the remembered destination folders are all editor preferences stored per user and per project. They are not part of Project Settings and are not checked in with the project.

Lightmaps

Control	What it does
Generate Lightmap UVs on Bake	Creates a lightmap channel for baked static mesh assets. Disable only for a fully dynamic/Lumen workflow.
Lightmap Texel Density	Global texels per meter. Resolution derives from surface area, rounds to a power of two, and clamps from 32 to 512.
Lightmap UV Padding	Approximate texel gutter between generated islands.
Set Component Lightmap Resolution on Bake	Applies the derived resolution to baked components; a per-actor density override takes priority.

Preset Library

Control	What it does
Auto Switch Preset Category on Selection	Changes the library tab to match a newly selected actor type.

The Preset Library asset path, managed thumbnail root, and baked registry are compatibility-managed internal settings and are not normally shown for editing. Keep their generated assets under source control when presets/bakes are shared.

Performance

Control	What it does
Enable Instanced Generation	Groups identical unbaked/runtime Wall pieces into ISM components. Bake-to-Components is unaffected. Disable only to restore the legacy per-piece preview pipeline.
Async Task Tick Budget Seconds	Maximum generation work per interactive frame. Lower values reduce hitches but take longer to finish.
Idle Async Task Tick Budget Seconds	Larger budget used after the editor has been idle briefly.
Edit Request Debounce Seconds	Wait before rebuilding after property edits, preventing regeneration for every slider tick.

Architect Mode, Streets Mode, toolbar, selection, conversion, and Preset Library view preferences are editor-per-user settings. They are described on the relevant pages and should not be treated as shared project defaults.