Game Development Reference
In-Depth Information
6
3D Modeling, 2D Graphics,
and Data Visualization
Living at risk is jumping off the cliff and building your wings on the way down.
—Ray Bradbury
6.1 SPATIAL PERCEPTION AND HOW THAT APPLIES TO
THREE-DIMENSIONAL MODELING AND VIRTUAL ENVIRONMENTS
You can model, build, or create whatever you can visualize if that visualization is based on careful, complete
observations of what you see in the real world. Look around your desktop. What are the qualities of the three
closest objects? What basic form do they remind you of most—a sphere, a box, or a cylinder? Where do the
highlights and shadows fall? What does the space around the object look like? Take a look at the basic prim
(primitive forms) in Figure 6.1. Note how they bend space around themselves by showing changes in the light-
ing on their surfaces. Each one has its own signature pattern. The sphere has a small round highlight, while the
shadows hug the opposite side like a dark band. The ring has a streak of highlight, and the shadow on the back
side starts with a straight-edged gradient. The box has no such gradients; each face is shaded in a solid color, a
highlight on the top face, deep shadow color on the back-facing side, and a somewhat middle tone on the other
visible side. You can never see more than three sides of a solid box from a single point of view. Rez a few of
these basic prims inworld and take a few minutes to observe the light and shadow qualities of the cylinder, the
torus, and the tube as well.
The knowledge that these basic forms can be combined to create any complex 3D content is the fundamental
key to modeling with the build tools provided within a virtual environment such as Second Life or OpenSim.
As you build, these forms should be constantly compared to the imagery recorded on your visuospatial sketch-
pad, your observations of the general scale of the avatar within the virtual environment, and how that relates to
what you are making. With this process you can maintain a context-related cohesive look to all that you build.
Remember, you are designing not only the 3D object but also the 3D space around it in a virtual environ-
ment. You control how 3D is seen and felt in your space, so why not make the most of it? One way this can be
done is by using the land controls in your viewer. With them, you control access to various areas or parcels and
thereby deine a path for the visitor. You can also control access by putting the avatar inside solid structures such
as tubes or hallways, or you can give them a tour vehicle with which to experience your virtual environment.
With scripting, you can change the size, position, color, texture, and visibility of your 3D models and have
them transform as they are approached and viewed, a great way to keep the experience fresh and interesting.
In the real physical world, we perceive 3D objects and their relationship to each other in space through a
variety of “depth cues.” Our brains observe the relative size of two objects, and we often assume the larger
one is closer to our position in space. By using the time-honored technique of forced perspective by building
objects some distance away in a smaller scale, or diminishing these objects in actual scale as they progres-
sively become distant, we can fool the brain into thinking these objects are even farther away. This is done
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