This tutorial is designed to show most of the UV mapping techniques and
tricks that I use day in and day out. This is more of a brief case
study rather than a step by step tutorial but it will give you, the
viewer, an idea of the work flow I use when UV mapping something tricky
like a human skull. I hope you enjoy it and learn something.
We will begin with a look at the model itself. Its always good to
unwrap Uvs on an object that is not to detailed because it can get
difficult to edit quickly and I am going to be using UVlayout which
automatically smooths and unwraps a models UVs and it can get very slow
if there are thousands of polygons to unwrap. The model is split into
three parts, I decided not to have the mandible as a separate object
from the rest of the skull because it can be easily split up in
UVlayout. The teeth though are separate because they will make a lot of
UV shells and its best to have them separate from everything else.
In figure 2
it shows the model being imported into UVlayout, in the
load options the new box is checked, this clears any previous Uvs
that are written into the .obj file. If the edit box is checked it
will import any Uvs written into the file so you can edit them.
The next thing to do if the object is symmetrical is to tell Uvlayout
to find its symmetry, this helps a lot because it mirrors over any cuts
you make to one side and when it unwraps the shells it makes both sides
match. This can be seen in figure 3
, also I have split up the mandible
and main skull object.
In figure 4
I have spent a little time cutting up the model into chunks
that can be easily unwrapped, the trickiest area was around the side of
the skull. It can sometimes take a while to get these things right,
there was a lot of back and forth with cutting up parts and seeing if
it unwraps well, and if it didnt unwrap well then I made adjustments
and unwrapped again etc.
In figure 5
, it shows the process UVlayout goes through as it unwraps the UV shell. It can sometimes take a few minutes depending on the
polygon count of the object. you can see I let it calculate a little
too long and there are overlapping UVs near the face of the skull, I
fix this later. Also notice that with symmetry on the UVs are identical
on each side.
It didnt take too long to unwrap the rest of the shells. You can see
in figure 6
in some of the UVs there are some areas of blue or red,
this means that areas with red arent getting an equal amount of UV
space in comparison with all the others UVs, and blue means the
polygons are getting too much UV space and green of course means the
polygons are getting the right amount of UV space.