UV editing

The UV page

With a mesh object in edit mode, the UV workspace shows its UVs: click a mesh object there (or press Tab with one selected). The page shows the UVs of the faces selected in the 3D view on the left, or of all faces (All faces), over the face material’s texture.

The units are texture repeats: 1 = one texture repeat, and what the page shows is what the game gets.

Sync (on by default) selects the UVs of whatever you select in 3D; picking UVs afterwards does not change the 3D selection.

Working on the canvas

Key	Action
1 / 2 / 3	Pick UV vertices, edges, faces (the same keys over the 3D view pick 3D elements)
Click / Shift+click / drag	Pick, toggle, box; a drag that starts on a selected UV moves the selection
A / Alt+A / Ctrl+I / L	All, none, invert, the islands the selection touches
G / R / S	Move, turn, scale about the middle of the selection; X / Y are U / V only, Ctrl toggles the snap, click confirms, Esc cancels
Wheel / middle drag	Zoom about the pointer, pan
U	The UV menu

Corners that share a 3D vertex move together only when they share the same UV, so an island stays stitched and a seam stays apart. Snap can be off, one texel of the material’s texture, or 1/2 to 1/32 of a repeat. The Position / Size / Turn fields type the selection’s bounds.

Projections, seams and unwrap

The UV menu offers box and planar projections (along X, Y, Z, the faces’ direction or the 3D view), a cylinder projection, Fit to 0..1 (keeping proportions), Stretch, Reset, Flip U / V and Rotate by 90 degrees.

Mark seam puts a seam (red in both views) on the edges selected in 3D. Unwrap flattens the selected faces cut along the seams, one island per piece, with no stretch where the shape allows, at real size, with v up on walls. A closed surface needs a seam first.

Seams are saved with the project and follow their vertices through extrude, inset, bevel, subdivide, loop cut, merge, separate, join and booleans.