Diagnostics, pivot, and lightmap tools

Diagnostics

Use Diagnostics and the baked registry before large rebakes, cleanup, or conversion. It is the authoritative view of current actor/bake state and tracked baked assets.

Randomize Seeds

Assigns new seeds to every actor in the level - unbaked and Runtime actors regenerate, baked output stays put. It is scene-wide, so record the seeds you care about first.

Pivot Tool

Select Static Mesh assets in the Content Browser, then choose Spline Architect → Pivot Tool.

Control	What it does
Pivot X / Y / Z	Anchor each axis at Min, Center, Max, or Keep. Defaults are center X/Y and minimum Z.
Pivot Transform	Adds a precise transform to the bounds-derived anchor.
Overwrite Existing	Repairs the selected mesh assets in place.
Suffix	When overwrite is off, creates copies such as _pivot.

Use copies first when the asset is already referenced. Moving a pivot preserves the visible mesh placement in the asset but changes how new actors, fitting bounds, and downstream tools interpret its origin.

Overwrite Existing, the pivot anchors, the transform, and the suffix are remembered between sessions.

Reset and Center Transform on an actor

The Reset Transform and Center Transform buttons on a Spline Architect actor move only the actor's own pivot. Everything it carries stays exactly where it was in the world - the spline points, and the attached actors including custom pieces. Reset Transform also preserves tangents and point types, so the curve between the points keeps its shape.

A locked custom piece is pinned against the generator sliding it along its spline, not against its wall moving. It travels with the building.

Lightmap Tool

Select Static Mesh assets, then open Spline Architect → Lightmap Tool.

Control	What it does
Unwrap Method	Fresh Unwrap (PatchBuilder), Fresh Unwrap (XAtlas), or cheap Repack Existing UVs. Repack requires a clean, non-overlapping source channel.
Source Channel	Existing UV channel for Repack.
Initial Patch Count / Merging Angle Threshold	PatchBuilder density and island merging.
XAtlas Max Iterations	Quality/time control for XAtlas.
Channel Mode	Override a specific channel (never UV0) or append the next free channel. Unreal supports up to eight channels.
Target Channel	Destination for Override Specific Channel. Existing data there is replaced.
Use Texel Density / Texel Density	Computes resolution from mesh size and texels per meter.
Explicit Resolution	Forced power-of-two resolution when density is off.
UV Padding	Texel gutter between islands.
Overwrite Existing / Suffix	Repairs in place or writes copies such as _lm.

PatchBuilder is the safest default for broken source UVs. XAtlas can reduce stretch on some meshes. Repack is fast but cannot repair overlapping UV topology.

Pinned toolbar

Pin the commands, presets, and shapes you reach for daily. It is on by default and purely for comfort; pinned state is a per-user setting, not project content.