UV editor

A dedicated 2D canvas. Click a face in 3D, the island lights up. Drag in 2D, the 3D face updates.

Toolbar UVRow 2 · DocksUVOpens the dedicated 2D UV editor panel in the bottom dock.Needs: A PBMesh opens the bottom panel. Pop-out detaches it to a floating window.

Canvas

Pan, zoom, a unit quad, optional texture underlay and tiling.
Wireframe of the islands.
Element modes on the UV toolbar: Vertex / Edge / Face / Island.
Channels UV1 / UV2 / Splat masks.
Snap toggle + step.
Frame Selection / Frame Unit Quad.

Transforms

Move / Rotate / Scale tools on the 2D toolbar. Flip U, Flip V, rotate 90° CW/CCW. Sew, split, collapse, stitch.

Projections

Button	What it does
Planar	Project along a chosen axis onto the selection
Box	Six-axis box map
Fit	Pack the island into 0–1
Unwrap	Angle-based unwrap

Texel density: read with Get, apply with Set, spinner in texels/metre.

Selection sync

Both directions:

Click a wall in the 3D view — its island highlights on the canvas.
Drag that island — the 3D face's texture moves.

Texture mode (6) is the 3D-side equivalent for quick rotates without opening the panel.

Splat masks — the paint debug view

The third channel is not a UV channel at all. Splat masks are authored in face-planar coordinates, normalized so each face fills the whole 0–1 square, and they travel in their own vertex channel (CUSTOM0) — never in UV2. The mask view draws that square for the selected face's material: the base texture with every painted layer and decal composited on top.

That explains the odd look on elongated faces: a splat in the middle of a long wall shows as a centered blot in a square, because the square is the face's paint area. The status line shows its real-world size (e.g. Splat area 4.00 × 0.50 m) so you can read the true proportions.

The mask view is read-only, by design. Selection works so you can inspect paint; the transform, projection, seam and texel tools go inert here. Splat paint and decals are edited by painting in the viewport — see Painting — never by dragging UVs.

UV2 and lightmaps

UV2 belongs to you: the splat system never writes it, whatever is painted on the mesh.

Unwrap it with the toolbar's Lightmap button (it also flips the mesh to GI Mode: Static, which is what the LightmapGI baker looks for), or set it up in a DCC, and rebuilds leave it untouched.
Paint, decals and geometry edits do not disturb it — you can keep painting on a mesh whose lightmap is already baked.
Paint can also be flattened to plain tile textures outside an export (useful when a consumer cannot run the splat shader): the repository's bake_splat.sh script does it in place, clears only the splat data and keeps UV2 — reference it or roll your own equivalent.

Use case — a stretched ramp

Select the ramp face. UV panel → Planar (or Box if it wraps).
Scale the island until the brick is square. Underlay on, so you can see the texture.
If two ramps should match, Get texel on the good one, Set on the other.

Export PNG dumps the current island layout for an external painter.

Auto-UV already handles axis-aligned walls. Open this editor for ramps, cylinders, and anything you merged across a crease.