80 ◾ 3D Animation for the Raw Beginner Using Maya
With our hand, we started out with a
complete “solid,” an enclosed cube, and
as we extruded our nger we continued
to maintain an enclosed model. But when
using extrusion with NURBS modeling,
we are going to start out with lines and cre-
ate surfaces from them. We will see that
our surfaces are not necessarily completely
enclosed. In fact, we will have to take some
action at the very end to nish up our
cactus so it does not have any holes in
its surface.
Again, there are no ironclad axi-
oms in 3D modeling. As we nish
our cactus, we will make use of com-
pletely enclosed NURBS primitives
(spheres). Correspondingly, we oen
create objects with polygon modeling
that are not completely enclosed. A
living room might start out with ve
separate planes arranged in a box with
one end le open to allow for room to
FIGURE 3.39 Extrude knuckle.
FIGURE 3.40 Add Divisions tool.
FIGURE 3.41 Divisions settings.
Modeling, Creating Materials, and Rendering ◾ 81
manipulate lights and cameras. We might
also punch a hole in a cube to make a door
or a window.
In this example, we also look at another
modeling technique, one that can be used
with both of Maya’s modeling mechanisms
(polygons and NURBS). It’s called sculpt-
ing, and it provides a way to carefully cra
an irregular surface, like a sculptor working
with clay.
Using Reference Images
We have seen that we can create 3D surfaces
by revolving a line in 3-space. ere are other
ways that we can use curved lines to create
organic surfaces with Maya.
Figure 3.47 shows a photograph of a
saguaro cactus, taken by my daughter
Martina. ey are big, old, and majestic.
Later, we will look at putting a material on
our saguaro.
FIGURE 3.42 Divisions on knuckle.
FIGURE 3.43 Vertex mode.
FIGURE 3.44 Move tool.
82 ◾ 3D Animation for the Raw Beginner Using Maya
FIGURE 3.45 Knuckle bump.
FIGURE 3.46 With a ngernail.
FIGURE 3.47 A saguaro cactus.
Modeling, Creating Materials, and Rendering ◾ 83
You can import reference images into a scene as “image planes” (in Maya parlance). You
associate these images with cameras. We will look at creating and using cameras in later
examples, but for now, you can go to:
any Main Menu → Create → Cameras → Camera
is creates a camera. We then select it and go to its attributes in the attribute box, and
choose:
Environment → Image Plane → Create
We le click the manila folder icon that pops up, then choose an image le from the le system.
We then go to the design area and choose:
Panels → Perspective → (select the new camera)
(e default name will be camera1 if this is your rst camera in this scene.) You will see
your image.
en, you can select:
Panels → Layouts → Two Panes Side by Side
You will nd your work area broken into two pieces. On one of them choose:
Panels → Perspective → camera1
On the other choose:
Panels → Perspective → persp
ese two pieces of the work area are showing in Figure3.48. And on the far right
of Figure3.48, we see the attributes of the image plane that has been created for the
camera.
You can break the work area into more than two panes if you have other reference
images. Many times it’s best to nd at least one more image taken from a 90-degree angle
with respect to the rst image. You then create another camera and assign the second
image to it as an image plane.
FIGURE 3.48 Two windows—reference image and persp view.
84 ◾ 3D Animation for the Raw Beginner Using Maya
Or, you can use a single panel in the work area, the one showing the image plane from
the perspective of a camera, and create your model in front of the image that is projected
by the camera.
Give it a try.
Let’s go back to our cactus reference image. We don’t need to import it into our scene,
because our model is going to be simple, and there’s no need to see it from multiple
perspectives.
One good reason to have a reference image is to use it to identify key visual properties
of the object you are modeling. is is particularly useful with an object that does not have
the sorts of complex geometry we oen nd with human-made things. With organic mod-
els, it’s oen simple geometric cues that trigger the right response from your viewer. You
don’t want someone to have to study your model for several seconds to gure out what it is.
For example, the trunk of the cactus widens at the bottom, as we would expect. e various
branches tend to be wide at the bottom as well, but each branch seems to start from a fairly
narrow base and then quickly swells outward and upward.
NURBS Extrude
Ever seen rain gutters being manufactured right on the back of a truck? ey are called
seamless gutters, because they can be tailored to t the dimensions of your house per-
fectly. e gutters are not prefab sections bolted together, so leaks are less likely to develop.
Instead, the gutter guy extrudes the gutter using the cross-sectional shape of the gutter. We
will do that to get our cactus started.
We will begin with a line again, since this is NURBS modeling. But this time, we want
to make it a straight line. Go to Create, then EP Curve Tool, as shown in Figure3.49.
Create a line that goes up and down, that is, in
the direction of the y-axis. Do not make it per-
fectly straight, but only lay down a few points.
Organic things are rarely ruler straight, but
our cactus wants to grow upward toward
the sun. e line should look like the one in
Figure3.50. Now, as in Figure3.51, go back to:
Create → NURMS Primitives → Circle
Create a small circle, like the one in Figure3.52.
is is actually a NURBS curve that happens
to end where it begins, creating a loop. Put
that circle at along the x-z plane, as seen in
Figure3.52. Shi-select the circle, and then the
line.
Now, as shown in Figure3.53, go to:
Surfaces Main Menu → Surfaces → Extrude
e result should look like Figure3.54.
FIGURE 3.49 EP Curve Tool.
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