You
can use the Smooth UV Tool to relax or
unfold an entire UV shell into the UV space. You can then use the
same tool to fix small imperfections in the shell.
The following workflow
provides the following benefits:
- It is easier to assign a texture to a
square area.
- Ensures the texture is spread evenly.
To map a shell to the UV space
- Create a mapping for your object by selecting Create
UVs > Planar Mapping from the Polygons menu
set.
In this case, a planar
projection from the front (the Z Axis) is appropriate. In other
cases you must determine the best projection to start with.
- Open the UV Texture Editor (Window
> UV Texture Editor).
- In the perspective view, select a path
of edges along the back of the head starting at the top of the forehead
and ending at the bottom of the neck.
- In the UV Texture Editor,
select Polygons > Cut UV Edges.
- Select the central UV at the top of the
forehead and in the UV Texture Editor, select Polygons
> Unfold > .
The Unfold
Options window appears.
- Turn on Pin UVs and Pin
selected UVs.
- Set the Unfold constraint
to Horizontal.
- Click Apply and Close.
The UV shell unfolds
relative to the selected UV on the forehead so that the previously
cut edges are spread out horizontally.
NoteRather than using
the
Unfold option, you can also
use the
Smooth UV Tool to unfold the
entire UV shell. In this case, you would select all the UVs except
for the one at the top of the forehead and then
+ drag
the
Unfold icon to the right.
- Use the Scale Tool to
scale the UV shell into the 0,1 texture space.
- Select the edges on one side of the mesh.
- Select Polygons > Straighten
UV Border.
The UV border straightens.
- Repeat steps 10 and 11 for each side
of the UV shell.
- Turn on the Snap to grids option.
- Select the Move Tool and
move the border UVs to the edge of the 0,1 texture space.
The Snap
to grids option ensures that the UVs snap to the border
precisely.
- Select all the UVs.
- Select Tool > Smooth UV
Tool > .
The Smooth
UV Options window appears.
- Turn on Pin Borders.
This ensures that the
UV border aren’t distorted.
- Set Space to UV
Space.
- Click Apply and Close.
Two controls named Unfold and Relax appear.
- Drag the Relax control
to the right.
The entire UV shell,
except for the borders, relaxes evenly.
With the Smooth
UV Tool you can use your eye to judge how much the UV shell
should relax. However, whether you use this method or the Relax option
(Polygons > Relax), it is
unlikely that the UV shell will be perfect.
If you turn on the Shaded
UV Display , you
can see small imperfections in your relaxed shell. For example,
the UV shell around the eyes and corners of the mouth for this model
cause the shell to overlap itself.
You can use the Smooth
UV Tool to smooth out these problem areas.
To smooth imperfections in a relaxed
shell
- Select Tool > Smooth UV
Tool > .
The Smooth
UV Options window appears.
- Turn off Pin Borders and
then select Apply and Close.
- Select a set of UVs around the eye.
- Drag the Unfold control
to the right until the UV shell no longer overlaps itself.
- Repeat for the mouth.
- You can select smaller or larger sets
of UVs and use the Smooth UV Tool in conjunction
with the transformation tools to quickly clean up your UV shell.