The Edit UVWs dialog contains three toolbars: one above the editing window and two below.
Contains controls for manipulating the texture sub-objects in the view window and setting options. When transforming with Rotate and Scale, pressing + will allow you to transform the selection from the point of the mouse click, instead of the selection center. The initial click specifies the center of the transform.
Pressing as you scale constrains the transform to a single axis.
After you select sub-objects, the Freeform gizmo appears as a rectangular bounding box around the selection. As you move the cursor over the gizmo's various elements and inside the gizmo, the cursor's appearance, and the result of starting to drag in this location, change:
+drag to rotate in five-degree increments; +drag to rotate in one-degree increments. Freeform rotation respects the angle snap status.
By default, scaling takes place about the gizmo center. If you've moved the pivot (see following item), you can scale about the transform center instead by pressing and holding before dragging.
Freeform pivot moved outside gizmo
If you +select one or more vertices outside the gizmo, the gizmo expands to encompass the entire selection.
Reverses the positions of selected sub-objects and flips UVs. Flyout options are Mirror Vertical, Mirror Horizontal, Flip Horizontal, and Flip Vertical.
Flip first detaches the selection along its boundary edges and then applies a Mirror Horizontal or Vertical, depending on the mode.
Toggles the display of the map in the editor window.
By default, the UV portion of the UVW coordinates is displayed in the view window. However, you can switch the display to edit the UW portion or the VW portion.
Contains all the maps of the material assigned to the object.
The names of the maps assigned in the Material Editor and in the Edit UVWs dialog (via Pick Texture) appear in the list.
Below the map names are several commands:
Choose a map you want to use in the view window. For example, you might use a bump or texture map as a reference to move UVW vertices.
A checker texture named CheckerPattern (Checker), useful for checking for distorted areas of the texture mapping, is built in to the Edit UVWs dialog. By default, this texture appears as the background texture when you first open the editor after applying Unwrap UVW to an object. To cause the pattern to appear on the object in viewports set to display textures, choose it from the drop-down list, even if it's already active in the editor.
The two lower toolbars include functions for selecting and transforming sub-objects and setting display properties.
The first of the two lower toolbars contains functions for setting the sub-object mode, making procedural selections, and using soft selection.
The active sub-object level is synchronized between the modifier stack and Selection rollout of the Unwrap UVW modifier and the Sub-object Selection toolbar setting. When you choose a sub-object level in one, it's also activated in the other. Similarly, selecting sub-objects in a viewport selects them in the editor and vice-versa. However, because you can toggle the sub-object mode via the modifier stack but not via the toolbar or Selection rollout buttons, it's possible for a sub-object mode to be active in the Edit UVWs dialog but not in the viewports.
Selects a loop of texture vertices, edges, or polygons. Usage is as follows:
Paint mode selects only sub-objects that are fully inside the selection brush. The dotted circle attached to the mouse shows the size of the brush. To change the brush size, use the Enlarge and Shrink tools (see following).
Increases the size of the UV Paint Selection “brush”: the circle attached to the mouse cursor.
Decreases the size of the UV Paint Selection “brush”: the circle attached to the mouse cursor.
These commands transfer sub-object selections from the base object (must be editable poly) to the texture coordinates and vice-versa. They are available only from the Customize User Interface dialog:
Soft Selection makes a selection of UV vertices behave as if surrounded by a "magnetic field." Unselected vertices within the field are drawn along smoothly while you transform the selection, the effect diminishing with distance. You can adjust this distance, or “falloff,” whether it applies to object space or texture space, and the formula by which it diminishes.
To use Soft Selection, first set a value that encompasses vertices to be moved or scaled, then transform sub-objects with a falloff effect.
The icons depict how their buttons affect falloff. The options are:
For an explanation of the difference between object and texture space, see this note.
These fields are active at all sub-object levels, but they always apply to vertices. With a single vertex selected, they display the current coordinates. With multiple vertices (or one or more edges or faces) selected, they display any coordinates the vertices belonging to the selection have in common; otherwise, they're blank.
When on, prevents you from adding or removing sub-objects from the selection. In this mode you can transform selected sub-objects without touching them.
When on, only selected polygons appear in the editor window; the rest are hidden. This option is supported at all sub-object levels, but applies to selected polygons only. Changing the viewport polygon selection automatically updates the display in the editor.
You can apply Hide repeatedly to reduce the number of displayed sub-objects incrementally.
When frozen, sub-objects cannot be selected or transformed directly, although they are subject to indirect transformation via soft selection.
Filters the object's material IDs. Displays texture faces that match the ID that you choose from the drop-down list. The list displays only IDs available in the modified object.
Click Pan View, then drag in the editor window to change the visible portion.
Click Zoom, and then click+drag to zoom the window.
Click Zoom Region, and then region-select (by dragging) part of the window to zoom in.
Zooms in or out to fit the texture coordinates in the window. The flyout buttons, from top to bottom, let you zoom to all texture coordinates, to the current selection, and to all clusters/elements containing any selected sub-objects.
When on, moving sub-objects tends to snap the vertex closest to the mouse cursor, which is highlighted by a square outline, to the nearest grid line or intersection.
This is the default tool on this flyout; Pixel Snap is also available.
You can set the snap strength on the Unwrap Options dialog.
Snaps to the nearest pixel corner when you have a bitmap in the background. Available from the Grid Snap flyout.
Combine this with Center Pixel Snap to snap to the center of pixels rather than the corner.