262 ◾ 3D Animation for the Raw Beginner Using Maya
MAKING GLASS BOTTLES WITH
NURBS AND MENTAL RAY
We return to glass now and consider three
variations on making glass. We will use the
same material for the three bottles we are
going to make and all three will have the same
outward geometry, but we will be trying out
some variations in the density of the geometry
of the bottles.
All three will be made from NURBS
geometry, but one will have very little
density in its geometry, another will have
extremely dense geometry, and the third
will have the same internal geometry as the
first, but we will tuck one copy of the bottle
inside another.
The Three Bottles
In Figure9.17, we see two bottles. e one to the right is a NURBS curve that has been
revolved in 3-space. e one to the le started out as the same bottle, but it was selected
and we chose:
any Main Menu → Modify → Convert → NURBS to Polygons
e model has been turned into a polygon model, which increased its geometric detail.
Next, we selected the bottle again and chose:
any Main Menu → Modify → Convert →
Polygons to Subdiv
is turned it into a subdivision object,
which further increased its geometric detail,
and the result is the bottle in the image. It was
converted one more time:
any Main Menu → Modify → Convert →
Subdiv to NURBS
is was done so that both bottles would be
NURBS models; but this last conversion did
not alter its geometric detail. Also, we cannot
continue to work with a model that is in sub-
division format.
FIGURE 9.16 Tiled texture.
FIGURE 9.17 Two NURBS bottles.
Light Fog, Fluids, and Another Look at Materials ◾ 263
Notice that the bottle on the le not only
has dense geometry; it also has a homo-
geneous swirly pattern, something that
we hope will result in interesting render-
ing eects. We have already made use of
the mia_material and its glass presets and
we will make use of it again. Accordingly,
we will be rendering with mental ray. In
Figure9.18, we have made an instance of
this material. In Figure 9.19, the reec-
tion color is set to a Caribbean blue so the
bottles will have a little color in them. is
will help separate the bottles from their
backgrounds.
mental ray Settings
In Figure 9.20, the mental ray renderer’s
Quality settings have been ramped up. In
particular, Max Sample Level is set to 2. e
raytracing Reections and Refractions have
been increased dramatically. In Figure9.21,
Global Illumination and Final Gathering
have both been selected. All of this might
increase rendering time signicantly.
A Bottle inside a Bottle
In Figure9.22, we have made a copy of the
bottle with the not-very-dense geometry.
We moved it over to the right, selected the
new bottle, did a Copy operation from the
Edit dropdown, and then did a Paste opera-
tion from the Edit dropdown. When we did
these copy and paste operations, the two
bottles ended up in the exact same place in
World space. We selected one of the copies
and scaled its x, y, and z dimensions down
to .95 of the original. ere are now two
bottles, one inside the other, and together
they form the third bottle from the le in
Figure9.23. Now, light will move through
the rst bottle, refracting, and then will hit
the second bottle and refract again.
FIGURE 9.18 Mia glass material.
FIGURE 9.19 Mia material attributes.
264 ◾ 3D Animation for the Raw Beginner Using Maya
The Render
In Figure 9.23, we see the three bottles.
Figure9.24 shows the render. e black and
white stripes behind the bottles will help
us compare the diering ways these bottles
reect and refract light.
Compare the simplest bottle, on the le,
with the bottle-in-a-bottle on the right. e
one on the right, as we might have expected,
seems to be made out of thicker glass. e
bottle has thick, black sides.
e bottle in the middle looks a lot
like the bottle on the le, except that the
reected and refracted light is jagged. is
FIGURE 9.20 is shows mental ray settings. FIGURE 9.21 More mental ray settings.
FIGURE 9.22 Inner bottle.
Light Fog, Fluids, and Another Look at Materials ◾ 265
phenomenon is caused by the complex swirling geometry that was a result of the conver-
sions to polygons and then to subdivision.
GLASS AND PARTICLES FOR A SINGLE-FRAME IMAGE
Maya can be used to make stunning single-frame images. 3D modeling programs are fre-
quently used to make lifelike images for magazine articles and ads, and for commercial,
governmental, and academic Web sites. We can also create more abstract art, images that
are not meant to be realistic but are meant to be eye-catching. We will try it with NURBS
and polygon modeling, along with glass and particle dynamics.
The Scene
Figure9.25 shows us the scene. We have taken the simple NURBS bottle we made previ-
ously, along with a glass made from revolving a curve. e glass has been converted into a
polygon model so that it can more easily be used to capture particles.
ere are two particle eects in the scene. Both were made by choosing:
Dynamics Main Menu → Fluid Eects → Fluid Containers
See Figure9.26, and note that this is a Dynamics eect, not nDynamics.
Fluid Containers
Maya has a capability for creating containers that will hold a volume of particles. It is
an easy way to ll a container with uid, as well as to create a ow of uid into or out a
container. We will use one emitter to create a uid stream from the bottle and another to
create particles that will ll the glass.
In Figure9.26, we are creating an emitter and a particle container at the same time:
Dynamics Main Menu → Fluid Eects → Create 3D Container with Emitter
Looking back at Figure9.25, we see the container that holds the particles that are com-
ing out of the bottle. Maya defaults to putting the emitter in the center of the container. But
FIGURE 9.24 (See p. CI-10 of Color Insert)
ree glass bottles rendered.FIGURE 9.23 Same shape but dierent geometry.
266 ◾ 3D Animation for the Raw Beginner Using Maya
we have pulled the emitter upward and tucked it just inside the mouth of the bottle, which
is just at the top of the container assigned to that emitter.
Figure9.27 shows the attributes of that emitter. Notice the –1 Buoyancy. at is the way
we will be able to make the particles go downward. We have also reshaped the container to
make it very tall along the y-axis, but very narrow along the x-axis and the z-axis. is is
to simulate a stream of uid.
Again, looking back at Figure9.25, there is a container inside the glass and it lls up
most of the space in the glass. Figure 9.28
shows the attributes of that container. It will
trap particles generated from its assigned
emitter. We have also given it a –1 buoyancy
value. We have le its emitter in the center of
the container inside the glass.
mental ray Glass
In Figure9.29, we have made a glass mate-
rial for both the bottle and the glass. We have
two instances of it: one for the glass and one
for the bottle. e attributes of the material
for the glass bottle are shown in Figure9.30.
Notice that the Refraction Color has been set
to a very light blue. In Figure9.31, we see the
attributes of the glass material assigned to
FIGURE 9.25 Glass for particles.
FIGURE 9.26 Create container.
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