Straightening

The UV Flow add-on allows you to straighten UV islands quickly in both the 3D View (Cut UV tool settings) and the UV Editor (UV menu). The operation performed is context-sensitive, depending on your selection, and can work on multiple islands simultaneously.

• Single Edge Selection: If you select a single edge, straightening will rotate the island so that the edge aligns with the nearest axis.

• Multi-Edge Selection: Selecting multiple edges will flatten any connected edge runs, align each edge or run, and then unwrap the remainder of the island around them.

• Quad or Patch Selection: If you select a quad or a patch of quads, straightening will align the quads to the grid and unwrap the remainder of the island around the straightened section. If the quads form a continuous ring, straightening will automatically add a split to unwrap it as a straight line.

• Triangle or N-gon Selection: If your selection contains a triangle or an n-gon, straightening will align the bounds of the selection to the grid and unwrap the remainder of the island around the aligned section.

When an island cannot be straightened into a grid or ring and falls back to alignment, islands containing edges on the mesh’s symmetry plane are rotated so the line of symmetry lands on the nearest axis. This keeps mirrored islands like faces upright.