This tutorial provides an overview of some advanced polygon
modeling and texturing techniques for Maya 4.0. It is my opinion
that polygon modeling is the best way to sculpt complex organic
shapes. (Special thanks to Dirk Bialluch who wrote a MEL script
called "Connect Poly Shape" which allows you to quickly set up and
sculpt a simple model while simultaneously seeing "the same"
smoothed shape as it changes. This MEL script is free and can be
downloaded from Highend3D.com.
) This tutorial
assumes that the reader possesses a basic knowledge of Maya
polygonal modeling tools as it does not provide in-depth detail for
every mouse-click, but rather an overall approach. GEOMETRY
In this tutorial, I chose to create a very old witch from
traditional Russian folklore. She is called "Baba Jaga" and is a
lonely woman living in the deep forest in a small wooden house and
is constantly doing bad things to other heroes of Russian legends.
First, I sketched the character in pencil because I didn't want to
restrict myself to a fixed image until I had a good idea of what I
wanted. I prefer to play with proportions and shapes on-the-fly. As
a result, I didn't put the sketch in ImagePlane, but kept it in
front of me for occasional reference. I created only one half of
the model and used mirroring for to complete the basic model
object. I first determined the right proportions, then created all
of the remaining parts. Next, I drew contours of all parts of the
model in Side viewport (e.g., head, blouse, skirt, and
), then extruded them out so that the contours defined my
I deleted the faces laying in original plane and applied the
connect PolyShape script with "Mirror and Stitch" option set to the
"-X" direction, "Stitch" checker box set ON and "Smooth Geometry"
parameter set to "1". Then using "Split Polygon Tool" I added more
details making the shape more rounded. Using the "Extrude Polygon"
tool, I made a very rough shape of the arm. The hands were modeled
as separate objects to make easier to modify their geometry.
Next came the process of splitting polygons and vertex-tweaking to
add details. It is very much like sculpting, when you remove all
unneeded clay and add more and more details to obtain the ideal
shape. During this process, a very useful trick is to hide all
unneeded objects using "View Selected" command from "Show" menu in
viewport panel. I also found that viewing objects in Smooth Shade
All mode provides more information about how the final geometry is
smoothed and allows you to clearly see where edges need to be added
and what can be deleted. The duration and instensity of this phase
depends on where you use your geometry and how close to the surface
you're going to show display it. Some of the mesh details can be
substituted by textures, say such as small wrinkles on the face.
Making all of the details at render-time using a texture channel
allows you to keep the polygonal count low. This technique is most
often seen in 3D real-time rendering games. In the this case, I was
planning to make fairly close-up renderings, so I thought it best
to make almost every detail using geometry rather than the quicker,
texture channel method.
MAPPING AND TEXTURE CREATION
Once the geometry is finished
it is time to create mapping and shaders. Creating mapping for
original geometry can be tricky as UV points are created for
"Smoothed" geometry as well. There are many ways to make create
good mapping. The following is the method that works best for me. I
wanted all UV points to be sewn into the smallest number of pieces,
preferably one or two to make painting textures more correct and
accurate later. In addition, if there will be additional editing
later in the process (for instance, in Photoshop
), it is
much easier to identify which texture image piece corresponds to
the model. Beginning with the head, I opened the "UV Texture
Editor" window (ctrl-T
) with the head model selected
(original, not smoothed
). This highlights all of the UV
points. I used the "Automatic Mapping" command and tried using
different numbers of projecting planes in its options dialog. I
found that when the number of planes is set to 4, fewer pieces are
created, which is what I wanted. Next, I sewed the pieces together.
Switching to the edges selection, I started from the region of the
head that corresponds to face. I started here because these are the
most important UV points for me. I then selected the border edges
of the biggest part of the UV network I and used the "Move and Sew"
command. One by one, I gathered all lost pieces of the UV network.
I then used the "Relax" command several times on some of the UV
points to make the network more regular. Finally, I used "Normalize
UVs" to fit all the entire network into the "0 to 1" UV space.
Creating the UV maps can be a cumbersome process, but I find that
it is not as slow as it seems, and it works well and gives very
accurate results. It is very important to remember that the further
the UV points are each from other, the bigger part of image is put
between them. For example, the eyes and the nose are the most
prominent and therefore important parts of a face, so it makes
sense to give them more of the image space than the other parts of
the face mesh. Another example of relative importance is the cheek,
which is much bigger than the eye but since it is plain and without
detail you could give it less of the texture map. If you simply
apply mapping according to geometry vertices you will get a large
UV space for the cheek and a small one for the eye, which is a
waste of texture. Keep this in mind when making corrections.
I created mapping for the other objects in a similar fashion. I
used the "Automatic Mapping" command only for complex geometry such
as head or hands. For the kilt and apron I used the usual
"Cylindrical mapping". Once the mapping is done, it's time to
create shaders and textures. I believe the Maya "3D Paint Tool"
with its ability to use Paint FX brushes is more than enough to
draw a good texture. In fact, in this image I didn't use any
extended applications to create the textures -- everything was done
inside of Maya -- the only exception was using photographed
textiles to create textile patterns! The subject of creating
textures is beyond the scope of this particular tutorial, however,
there are a few tips I can provide:
- Give accurate and descriptive names to objects and shaders,
it helps to keep order in texture files.
- Don't use JPEG textures if you need good quality final
renderings. JPEG compression changes the original colors of an
image and you might be surprised when doing close renderings to
find that you get color spots on an originally flat surface! Using
TIFF textures offers more accuracy and better rendering quality
though TIFFs take up much more space on your machine.
- Final colors created out of many passes and layers are more
alive and beautiful, and subtle.
- Start with big color spots and gradually add more small
- Don't use Black - use close colors -- say, very dark blue
or dark brown.
- Make detailed dark spots and regions in the last
- Always give attention to obtrusive parts, or prominent parts
that "stick out," with brighter colors since that helps show the
- When drawing bump textures, it is helpful to do test
renderings to see how they work together with color
- Finally, map the "Incandescence" of almost all shaders with
the "U Ramp" node, and the "U coord" parameter connected to the
"Facing Ratio" parameter of the "Sampler Info" node.
After finishing with shaders, I created hairs and eyebrows using
the "Paint FX" tool. To make strokes align accurately with the
geometry, I was forced to create additional NURBS surfaces to use
them as "Paintable objects" ("Make Object Paintable" command
under the Paint Effects menu
). Unfortunately only NURBS objects
can be made paintable. To create the NURBS surfaces, I made the
Head object "Live", and then drew several curves near the eyebrows
and regions where hairs would be seen. I then used the "Loft"
command to create reference surfaces that could be used as
"Paintable Objects" during later editing. After all the strokes
were painted and I was happy with their shapes, I attached them to
one brush node using the "Share One Brush" command. I then tweaked
their parameters to achieve the desired look.
That's it for the creation of the actual mesh! The rest of the
image entails setting up the environment, a lighting scheme, a
skeleton and character rigging to give her a natural pose and, of
course, the rendering!
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