UV Relax

Allows you to choose from various modes that control how the Relax tool acts upon the target UVs.

Spring - Generates a 2D dynamic simulation that makes all the edges in the UV map act like springs, each pulling on the others to find their equilibrium. This method doesn't deal with overlapping UVs very well.

Conformal - Relaxes the mesh using the ABF++ (Asynchronous Forward Bounding) algorithm to smooth out the UV map, as with the Unwrap tool.

Adaptive - An adaptive attempt to retain the original relative polygon size from the 3D mesh surface.

Angle Based - Uses the LSCM (Least Square Conformal Maps) algorithm to smooth out the UV map, as with the Unwrap tool.

Determines the number of iterations for unchanged iterations. Increasing the Iterations relax/smooth the geometry; the degree of iteration necessary is largely dependent on the complexity of the target mesh.

The interactive mode offers you an amazing way to edit a UV map using Pins. When Interactive is enabled, you can click over any vertex in the UV map, adding a blue square handle to it. When there is more than one handle in the map (and a sufficient number of Iterations) you can interactively drag around the UV map to reshape the layout, as if it were a sheet of rubber that twists and pulls between the your added Pins. Removing pins is done by Ctrl/Cmd+clicking over an existing pin. You can add as many handles as necessary, but fewer handles usually provide the best results. Use the Save Constraints checkbox if you want Modo to remember which vertices were set as pins each time the tool is used.

If the target mesh isn't "water-tight" (such as a head model with open eye sockets) the Relax algorithm can sometimes have difficulty resolving these areas. The Seal Holes option creates a virtual polygon to close the holes and improves the unwrapping effect.

Determines how to relax boundary UV vertex positions. The following options are available:

Smooth - Locks boundaries off and relaxes both the boundary edges and the inside UV vertex positions.

Locked - Locks the outer boundary edge of all UV islands and only relaxes the inside areas of geometry; the outer edges act like pins constraining the connected edges.

(A UV island is a connected group of polygons in a UV map.)

Click on the image below to view an animation.

Maintain - Ensures boundary points only move along the boundary to keep the angle between boundary edge and incoming inner edge. In other words, it ensures that the boundary points only are moved along the boundary, not towards the interior of the surface. For example, when starting with a symmetrical UV map, such as a model created by the Unwrap Symmetrize function, enabling the Maintain option retains the symmetrical properties of the map while relaxing.

Straighten - When this option is enabled, boundary edge sections of the UV islands are straightened and the internal points are relaxed inside the new boundary. This is useful when aligning UVs for piped shapes or hairs.

Creates uniform spans for UV edges. This option is enabled when the Boundary has been set to Straighten.

Temporarily disables the iterative updates to allow pinning to be applied without continual updating of the relaxed results. Disable the Pause function to evaluate the relaxation with the updated settings.

Using the Adaptive relaxation mode, the Area Weight option determines a weighting applied to an area to allow it to resist changes from the relaxing of the UV vertices of the modified UV island.

Using the Interactive option to pin vertices, the Save Constraints option saves which vertices have handles and keeps them intact for the next time the tool is applied.