New Box 

This creates a new packing box around any picked shells. Shells can be place in or taken out of an existing box simply by dragging them with the usual Space-MMB combination. Use the Del hotkey to delete a box; moving all of the shells outside of a box will also delete it. Click on Delete All to delete all boxes.

Use the [ or ] hotkeys to repack the box under the mouse pointer. If no box is under the mouse pointer, then all shells and boxes will be packed into the 0-to-1 texture square.

A box (and its contents) can be moved around using the Space-MMB combination on one of its corner handles. It can be reshaped using Ctrl-MMB on one of these handles; this will also repack that box. Use the \ hotkey to rotate a box by 90 degrees.

Select boxes by clicking on one of their corner handles, and they can then be moved or scaled with the usual Space MMB/RMB combinations. Selected boxes can also be transformed from the Move/Scale/Rotate panel buttons.

By default, boxes are free, meaning they will be moved around as required during the packing process. You can fix a box's position with the { or } hotkey; this will turn it from green to blue. Other shells and boxes will then be packed around that box, but it wont be moved itself. Use the same hotkey if you want to toggle it back to free moving.

Box and Lock Overlapping 

If you have overlapping shells that you want to keep together during packing, then click this button and they will all be boxed and locked. Be default all visible shells will be checked, but if you LMB select any first, then only those selected shells will be processed.

Unstack Overlapping 

If you have overlapping shells, but don't want them to be, then click this button and they will be moved across, then up if need be, to empty locations in adjacent UV tiles. Its different to the normal packing because shells don't change their relative positions within tiles with this tool. By default all visible shells will be moved, but you can LMB select to limit the action to just the selected shells. If the packing tool's Tile U dimension is greater than 1, then that is the maximum width of tiles unstacked to, otherwise the Display Max U setting is used.

Allow Box Overlaps 

Sometimes space will be left inside a box after packing. Ticking this option will allow other boxes or shells to use this empty space during global packing operations.

Shrink Boxes To Fit 

Tick this to shrink wrap boxes around the contents after packing.

Tile 

If you want your shells and boxes packed across multiple tiles, specify the dimensions of that tile grid here. Try not to make the grid arbitrarily large (e.g. 100 x 1) if smaller values will do, as this will reduce the precision/tightness of the packing.

Lock All To Tile 

Shells wont be moved outside of their current tile during packing. Ticking this option affects all shells, or you can use the # hotkey to apply the locking selectively to shells and boxes.

Don't Resize Tiles 

By default, UVLayout will uniformly enlarge or shrink the UV tiles to minimize the amount of empty space left after packing. Tick this if you don't want the tiles resized.

Pack Tiles 

If you have shells spread over many tiles with empty tiles between or lots of empty space within them, this tool can quickly compact everything. Its different to the normal packing because shells don't change their relative positions within tiles with this tool. Be default all visible shells will be moved, but you can LMB select to limit the action to just the selected shells.

Bleed 

The Bleed value controls the size of the gap left between shells after packing. You can select between pixels or real world units (for pattern making applications).

Show Shell Bleeds 

Tick this to see a visual indicator of the pixel bleed region around each shell. If you want to manually position shells, this is a good way ensure there's enough gap left between them.

Quality Fast/Mid/Best 

You will get tighter packing with Best selected, but Fast isn't too bad either, and its a lot faster. Mid is part way between these two.

Map Rez 

Specify here the resolution of the texture map you expect to use with the UVs. This in combination with the Bleed value determines the apparent size of the gap left between the shells after packing.

Use Trace Mask 

This option allows you to load a black and white Display Trace image as a mask for packing shells into the UV square. Shells will be packed into the white areas, and black areas will be left empty. [Example]

Allow Wrapping 

This option packs everything into the 0 to 1 tile but will allow shells to extend over the boundary of the tile if they wrap around into space on the opposite side. To check the results, tick the Show Repeats option under the Display tab. [Example]

Pack Selected Only 

Only shells selected with the LMB will be packed.

Pack All 

Clicking on Pack All will repack the contents of all boxes, then packs everything into the 0-to-1 texture square or tile grid. You might do this if you have changed the Bleed setting and want to apply that across all shells and boxes.

Show Tile Coverage 

Tick this to show, after packing, a percentage covered value at the top of each tile. The higher this number the better, indicating less empty wasted space.

Hotkeys 

[ or ]      : pack shells in box, or if no box is picked, packs all shells
{ or }      : toggle box fixed/free status
\           : rotate box, shell or tile 90 degrees
Ctrl-\      : rotate shell inside a box
Del         : delete box
|           : toggle orientation lock for shell, selected shells or box
Pad 1/3/7/9 : toggle corner preference for shell, selected shells or box
#           : toggle tile lock for shell, selected shells or box