UV Sculpting

Reference

Mode:Paint Mode and Mask Mode
Panel:Tools Shelf ‣ Options ‣ UV Sculpt, Tools Shelf ‣ Tools
Menu:UVs ‣ UV Sculpt
Hotkey:Q

The UV Sculpting "mode" allow you to grab, pinch and smooth UVs, just like Sculpt Mode. It can be activated with Q or by checking UV Sculpt in the UVs menu.

UV Sculpt

When UV sculpting is activated, the Toolbar shows the brush tool selection and options.

Lock Borders
Locks the boundary of UV islands from being affected by the brush. This is very useful to preserve the shape of UV islands.
Sculpt All Islands
To edit all islands and not only the island nearest to the brush center when the sculpt stroke was started.
UV Sculpt Tools

Brushes that operate on UVs. All brushes use the Airbrush Stroke Method: they continue to act as long as you keep LMB pressed.

Grab G
The Grab brush moves UVs around.
Relax S, Shift-LMB

The Relax brush makes UVs more evenly distributed. The algorithm relies on space, not stretch minimization, so most probably a minimize stretch will have to be run for optimal results. However it is great to use after stitching islands, or when unwrap produces cluttered results to smooth the distribution of UVs.

Relaxation Method

There are two relax algorithms:

Laplacian, HC

Pinch P
The Pinch brush moves UVs toward the brush's center. The pinch brush can be inverted by pressing Ctrl-LMB.
Show Brush
Hides the sculpt cursor.