Modeling the Hands
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| Figure 1: Sketch as a reference |
Similar to the face, the human
hands contain many details that can make modeling difficult. It is therefore
recommended to first work on the basic shape of the hand and fingers and to add details when
necessary. Complex structures like the raised veins on
the back of the hand or the
deeper creases at the knuckles and finger joints can often be simulated with textures. Thankfully,
all fingers are built in a similar manner, even though they differ
in length. This will save us some work, as we will see
during the modeling process. As
with all modeling, there first should be thorough research for
references. Different from the face, for which a mirror is needed to model from, hands are always
in our line of sight. Thus, our own hands should be used
as reference as well, even
though they might be male hands. The structure of male hands is identical to female ones. In
our case I look for photographs that, as described in the first
chapter, match in size and position, and trace their contours. Figure 1 shows the result. This helps us to keep our focus on the essential
shapes.
Especially important is, besides
the size of the hand, the position and appearance of the fingers. Fingers are rarely
completely straight and their length differs greatly from
one person to another.
Special attention should be paid
to the thumbs. It is especially common for beginners to attach the thumb at the side
of the hand. This might be true when the hand is pressed flat on a table, but when it is
relaxed or grabs something, the thumb rotates away from this plane and is then almost in
a position perpendicular to the finger plane. In order to be able to generate
different poses of the hand, it should be
modeled in a relaxed pose.
Fingers
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Create a basic cylinder object without caps. The object should look just like a pipe.
Subdivide the pipe into eight
parts. The pipe now looks like an octagon. Since the
object will be rounded later,
this number of subdivisions is sufficient.
Place the cylinder over the
top-view image template and adjust the radius and length
to the shape of the middle
finger. This is the longest finger of the hand.
Before you start adjusting the
outer shape of the octagonal pipe to the fingers, add
more subdivisions where the
finger joints are located. One of the three subdivisions is
placed exactly in the middle of
the joint, and the other two subdivisions border the outer
area of the joint where the
deepest creases are located.
The upper screenshot in Figure 2 shows the result of
these subdivisions. In the lower
part of the figure the octagonal
profile of the pipe can be seen.
The additional subdivisions at
the joints have two benefits. We define an area
where the creases can be easily
created. The second, more practical use is that
because of the subdivision at
the joints, the hand becomes mobile in 3D programs. By
adding deformers, these areas
can later be bent and the fingers moved.
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| Figure 3: Shaping and closing the cylinder |
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| Figure 4: Selection of the fingernail polygons |
It is, therefore, important to
place these subdivisions on the joints as exactly as
possible. Then begin in the next
step to adjust the shape of the pipe to the image template. As we can see in Figure 3, it is a three dimensional procedure
because the shape
should fit in the top view as
well as in the side view. Use the subdivision at the joints on the
underside of the fingers to
create a distinctive groove. Note that the finger thickens mainly
at the first joint. This is not
so distinct at the joint closest to the tip of the finger.
When you are pleased with the
result, add another point at the fingertip and connect
it, with quadrangular faces, to
the front edge of the pipe. The finger is now closed
at the fingertip. The base of
the finger remains open.
It is also important to arrange the fingers along a slight curve and not in a straight line
like the teeth on a fork. Another thing to consider is that the transitions
between the fingers are not shaped like a V but are more round. We will get into that
during the modeling process later. Start by loading the created image
templates for modeling the hand into a new, empty scene and place them
according to the editor views.
Fingernails
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The fingernails are the most complex part of the finger. They grow out of the finger
and are connected to it at the base end, while at the other end ,
they are completely
separated from the tip of the finger. The skin borders the nail
bed and along the
side of
the nail, and bulges slightly upward. We start by selecting the two polygons at
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| Figure 5b: Extruding the nails |
the upper part of the fingertip. From these faces we will model
the nail bed and the nail
itself. Figure 4 shows this selection from different perspectives.
Because the finger should bulge next to the nail and the nail at
its base should disappear
inside the finger, we cannot use these faces directly for the
modeling of the nail. We first
have to create a base. Therefore, extrude these two faces and
shrink the resulting faces slightly. Move the new points located
at the nail bed
slightly downward and in the direction of the leading finger
joint. Figure 5a indicates
these two steps with arrows. This base is then extruded another
time
but this time mainly upward, vertically. The height of this
extrusion determines
the thickness of the nail. The height of the extrusion can be
slightly less at the base of
the nail since this is where the nail disappears under the skin. The
necessary move is indicated in Figure 5b with the arrow pointing in the direction of the first joint. The
amount of movement will later be checked on the smoothed object. If necessary,
pull the edges of the extruded nail further upward in order to frame the nail
more by the finger. At the base and
sides of the nail it shouldn’t look like the nail was placed on
top of the finger. Only when
the nail reaches the fingertip should it be slightly separated
from the finger. Depending on how long the fingernail should be, the shape can
now be finished with the
available polygons. A possible result can be seen in Figure 5c. Note the area of the nail
bed where the nail polygons are moved far into the finger to
better integrate the nail.
When the nails are longer, the polygons in front of the nail
should be extruded, as
shown in Figure 5d. This allows you to adjust the shape of the nailtip more
precisely.
Subdivide the edges that border the joints on the underside of the
finger, as shown in
Figure 5e.
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| Figure 5c: The finished fingernail |
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| Figure 5d: Extending the nail |
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| Figure 5e: Creases on the underside of the finger |
Joints
To create the creases under both joints, we need more subdivisions
in these areas.
This is where we create V-shaped indentations. Two indentations at
the joint
closest to the base of the finger and one at the joint near the
tip should be enough.
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| Figure 6a: The upper creases on top of the joints |
On top of the joints we create rhombic or circular subdivisions,
as can be seen in Figure 6a. This is similar to the concept
of the polygon loops that we used when modeling
the face. Especially at the larger second joint in the middle of
the finger, it is apparent that the creases of the skin are running in an
elliptical course around the joint when the finger
is extended. The only exceptions are the creases that are located
directly above the
joint. These cross the finger perpendicular to the direction of
the bone.
This circular arrangement of the faces can be used to reproduce
the creases. This loop
also helps us to limit the number of faces needed in the area of
the joint, so we don’t
have to make so many cuts through the whole finger. Too many cuts
could result in
problems on the underside of the finger. We need at least two
additional vertical
cuts on the second joint, since the area of the creases there is
quite large and we will
need to create at least three more creases. The smaller creases
can be added later with
a material. The additional edges can be seen in the side view of
the finger in Figure 6b.
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| Figure 6b: The creases of the joints |
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| Figure 6c: The smoothed view of the finger |
Lower the edges over the joints slightly so a small indentation
appears.
Skip the following edge loop and lower the next one. This creates
a zigzag shape on top
of the joint that will result in nice creases when smoothed. Don’t
overdo the depth of the creases on the finger. After all, these should be the
hands of a young woman. The rules that apply to the hands also apply to the
face: Creases are added only where they are necessary for the function of the
joints, muscles, or skin, or support the character of the person. Creases caused
by age generally don’t need to be added. Also note how additional subdivisions
at the underside of the fingers are used to narrow the joints and to add more
volume to the area between the joints. Figure
6c shows the smoothed version of
the finger model. Clearly visible are, especially on the underside
of the finger, the voluminous
areas between the joints, bordered by the joint creases. This is
the location of the muscles
that
give the fingers the ability to move. Also take note that
the last portion of the
finger,
meaning the fingertip, is modeled to appear very soft and voluminous. This
prevents
the finger from appearing too pointy.
Remaining Fingers
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| Figure 7: Scaling and placing the finger copies |
As mentioned at the beginning, the fingers differ mostly with
regard to thickness and
length. The basic construction of each finger and the proportion
of the segments between
the joints, with relation to the overall length of the finger, are
the same.
Therefore, we can use the modeled finger as a base for the
remaining three fingers.
I deliberately exclude the thumb since it contains a different
order of joints and even
lacks one near the tip. But even with the thumb we will use parts
of the basic model of a finger and save ourselves a little work. We
start by duplicating the existing finger and moving the new object so it fits
the sketch of the index finger. The profile of the middle finger and index
finger are almost identical. Therefore, when changing the size,
only the length should be changed. Because the fingernails stay
the same,
regardless of the length of the fingers, reducing the length of
the fingers should
be achieved by shortening the segments between the joints.
As a basic rule, the shorter middle segment of the index finger,
compared to that of the
middle finger, makes the difference in length between these two
fingers. By comparison,
the ring finger has a shortened segment between the hand and first
joint.
With the little finger, the first two segments are shortened,
meaning the segment
between the hand and the first joint, and the one between the
first and second
joints.
Keep this in mind when copying and scaling duplicates
of the basic finger. Also
use
the image templates, which show the length of the fingers when viewed from
above,
as a guide. After a first rough placement, correct the
shape
of the fingers. As mentioned before, fingers are seldom completely straight.
Rather,
the fingers, when placed next to each other, angle toward each other,
especially at
the
fingertips. When considering the palm of the hand as the base, the overall
shape of the fingers looks like a triangle. The fingers don’t just run straight
out of the palm.
In
addition, the fingers, with their complex joints and tendons, follow, at their
base,
the curve of the
rounded shape of the back of the hand. The fingers
therefore vary in
height as well as in length. As can be seen in Figure 7, the fingers form
a soft curve. It is important to consider this so the hands don’t
appear unnaturally stiff.
This curve is continued on the side toward the thumb, which we
still have to add and
which, of all the fingers, has the most spacein which to maneuver.
Palm Object
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| Figure 8a: A cube as the base for the palm |
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| Figure 8b: Adjusting the shape of the cube |
Before the missing thumb can be added, the basic shape of the hand should be created.
This contains the back and the palm of the hand. These faces
connect the fingers to
each other and end at the wrist where the forearm connects. In order
to keep to a minimum the number of faces connecting the hand to the arm, the
number of faces at the wrist, where the forearm connects, should be reduced. We start with the modeling of the basic
shape of the hand. The object to use would be a basic cube, as
shown in Figure 8a.
In order to have enough faces available to connect the fingers,
the cube should have
eight subdivisions in its width, three in its length, and two in
its height. This results
in four polygons for each finger on the front surface. Move the
points at the front surface of the cube so that a small gap remains between the
fingers and the cube.
In the side view adjust the position of the faces of the front
surface so four polygons
are centered behind the open end of each finger cylinder.
This results in a slight bulge of the back of the hand, as can be
seen in Figure 8b.
Then unite the fingers and the new cube to a single object so we
can create connecting
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| fig 8c |
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| fig 8d |
The fingers can now be connected, on top and bottom, directly to the now open edge of the cube. Simply merge the lateral points between the fingers, as can be seen in 8c. Add another subdivision to the transition between the fingers and the hand, at the base of each finger. This prevents this area from appearing too pointy. Then delete the faces that previously connected in the middle. The result is an opening as shown in Figure 8d. Combine the middle and lower points of the edge of the opening. These points are marked in white in Figure 4.17.
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| Figure 8f: Edge selection |
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| Figure 8e: The new finger base |
is marked in red in Figure
8e. Part the edges in the area between the fingers, as
shown in Figure 4.18. This area represents the skin that looks like a web when the
fingers are spread apart. The connection of the fingers is now complete for the
upper part of the hand.
However, a look at the underside of the hand reveals that contours
are missing. The
fingers appear to simply grow out of the hand without creases,
which indicate the
joints above them.
Also, there is still a lack of subdivisions that could create
these details sufficiently.
Select these edges at the underside of the hand, where the fingers
connect. Expand
this selection to the middle of the edge of the hand and to the
area between the index
finger and the still missing thumb. Figure
8f shows the path of the edge selection
in red. Double or part these edges to get two parallel edges. Figure 8g shows the result
of this action in red. Then delete the connecting faces in the
area between the fingers. The resulting gaps are also shown in the image above.
Close these holes with new faces, as shown in red in Figure 8h. These faces can
be used to further shape the skin between the
fingers. The newly created edge is then moved upward toward the
finger knuckle and
thereby creates a crease, as shown with arrows in Figure 8h.
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| Figure 8g: Parting the edge selection |
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| Figure 8h: Closing the holes again |
Back of the Hand
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| Figure 9: Shaping the Back |
Depending on the position of the hand, the back of the hand can be
flat or, when making
a fist, is shaped by knuckles. It also shows tendons when the
fingers are spread.
We will discard blood vessels for now. These can be added later
with a texture, just as
long as they are not so defined. However, even if knuckles and
tendons are
not to be very pronounced, the subdivisions should still exist.
This gives you the freedom
to attach these details to certain positions of the hand when, for
example, morphing
the surface. Generally speaking, just a few faces have to be added
since only the surface is raised slightly. Therefore, select four polygons on top
of each knuckle and an additional four
polygons between each knuckle and the wrist. Extrude these faces
and scale the
results slightly. The corresponding faces are marked in red in Figure 9.
Depending on the desired definition of this area, move the knuckle
faces upward. The
faces for the tendons should be raised down the middle so only
small segments protrude.
Reverse this in the middle of the hand so the tendons disappear
completely under the skin
again, keeping this effect more subtle. It is important that the
tendons not remain
parallel, but instead move closer to each other as they head
toward the wrist.
Thumb
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| Figure 10a: Modeling the thumb |
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| Figure 10b: The assembled thumb |
Now we get to the thus-far-disregarded thumb. It has, as we can
see on our own
hands, one less joint and is more compact and thicker than the
other fingers. Nevertheless,
we will reuse parts of the existing fingers. For that reason,
separate a copy of a complete
finger from the hand. Keep the complete tip of this finger,
including the nail and the first
segment with the joint. Move the two remaining segments of the finger
toward each other until the length of the thumb is achieved. Increase the circumference
of the object to create the thickness of the thumb. The upper image of Figure 10a shows this end
result. Rotate the thumb around its length axis until the side of the
fingernail points upward. Make sure that the base of the thumb follows the
curve of the other fingers. Then connect the two separate segments of the thumb
with each other, as shown in Figure 10b. In addition, widen the opening of the thumb above the joint.
Then delete the faces along the side of the hand next to the index finger and
create new connecting faces that connect the thumb with the hand.
These faces marked in red can be seen from different perspectives
in Figure 10c.
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| Figure 10c: Connection between hand and thumb |
Adding Details
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Figure 11a: Thickening of the underside of the hand |
The basic shape of the hand is now recognizable, but there are
still details missing from the transition of the thumb to the hand and from the
underside of the hand. We will start with adding volume to the base of the
fingers. The extrusion depends on how meaty the hand should appear. The
extrusion should be a little on the lighter side, since it is a female hand.
With a male hand this area could be more pronounced, since calluses often
appear there.
Figure 11a shows in red the
resulting polygons after the extrusion. Depending on the shape of the hand,
this area could be extruded as a continuous strip and not separately above each
joint. This can also help to border the lifeline that begins at the edge of the
hand.
Muscle at the Base of the Thumb
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| Figure 12a: The bulge at the base of the thumb |
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| Figure 12b: Shaping the muscle groups |
So far, the palm of the hand does not have enough subdivisions to
show details like single lines or to model the bulges. Therefore, we will add a
continuous subdivision in this area. As you can see in Figure 12a, the path of this
cut goes through the polygons on the back of the hand, continues to the base of
the thumb, and through the crease at the joint. At the inside of the hand, the
cut curves again in the direction of the palm and connects at the edge with the
starting point of the cut. Add a continuous cut at the base of the thumb, as
can be seen in the top image of Figure
12a. Use these new faces to better control the shape of
the thumb in the area of its base. Move the new edges of the inside of the hand,
in the area of the ball of the hand, downward. This spot is marked with an arrow
in Figure 12a. The
goal is to simulate
the bulge of the thumb muscle in the palm. The characteristically
round shape of this muscle is still missing. The points in this area need to be
moved in order to restrict this area. Figure
12b shows this step. In Figure 12b you can see how the additional points and edges,
created by the last cut at the base of the thumb on the underside of the hand,
were moved in the direction of the base of the fingers. A similar movement is
also necessary in the area of the outer edge of the hand. Located here are
larger muscles that bulge out from the palm of the hand. Between these two “hills”
the palm recedes slightly and creates a dent. In the center image of Figure 12b, you can see this
dent at the location of the thin red arrow of the coordinate system of the
hand. Use the faces located between the wrist and the previously moved edges to
shape the described muscle groups. In an unusual view, originating from the
wrist, the volume of these muscle groups and the resulting dent in-between can
be seen very well. In the next step we will refine the transition to the thumb.
Here too is the characteristic
stretching of the skin when the thumb is spread out, as we have
already modeled between
the other fingers.
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| Figure 12c: The stretched skin at the base |
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| Figure 12d: Emphasizing the muscles thumb |
Select the connecting faces between the thumb and hand and extrude
them. Slightly
shrink this polygon group and pull these faces slightly outward. The
image series in Figure 12c shows these extruded faces in red. As can be seen in the last image
of the series, a nicely defined web of skin has been created. Additional
details should be added to the
palm if this part of your 3D character is to be visible very
often. A reason for this is that
the muscle at the base of the thumb should have a more visible
border at the wrist and
at the center of the palm. This is accomplished by extruding all
faces and then shrinking the new polygons. Figure
12d shows the corresponding selection in red. Use the
newly created points at the edge of these faces to create a crease at the wrist
and in the center of the palm, as shown in the lower image of Figure 12d
Wrist
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| Figure 13a: Transition to the wrist |
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As mentioned before, the faces in the area of the wrist should be reduced so fewer
subdivisions transfer into the structure of the forearm. First,
extrude the oval edge at the open end of the hand, doing this twice. These additional
subdivisions are necessary so the
hand can later be bent at that spot. Then pull out, a little bit,
every third point at the open edge of the wrist. A zigzag structure is created,
which can be seen in Figure 13a.
This irregular shape allows us to create quadrangular polygons in
the next step. These again create a closed and smooth edge. These new faces are
highlighted in color in Figure 13a.
As you can see, the shape of the object has not been changed, but
the number of
polygons at the wrist has been reduced to just eight. Simple
parting of edges can be used when more details are needed on the palm. Figure 13b shows an example. However,
this can only work without problems when the edges already run in the direction
of the desired creases. Therefore, pay attention to the structures of the palm during
modeling. This concludes this complex step, and we can now take a final look at
the finished model (Figure 14).
Final Result
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