Graphics Reference
In-Depth Information
both camera and light perspectives are tied to actual objects in 3D space. Thus, if you move these views, you
will actually be moving (or rotating) objects and changing the makeup of the scene. Movement in camera
and light perspectives can be reversed with the Undo command, but movement in the generic perspective
view cannot be undone.
A common analogy is that if an Adobe Photoshop (or other 2D graphic) image is like a painting, a 3D
document is like a sculpture. Two-dimensional art forms (digital and analog) use space, form, and color to
create the finished image. Depth and dimension are created through color variation for simulation of light
and shadow. Three-dimensional art adds volume to the mix, which offers more-concrete simulation of real
light and shadow. Because 3D provides added levels of realism, you need to consider additional parts of the
creative process in order to create compelling 3D art.
Exploring a 3D Scene
The next things to consider when beginning to work in 3D are the individual pieces of a 3D scene and the
steps in the creative process that will result in a finished project (a model, still image, animation, and so
forth). This space is filled with points, edges, and polygons that create the objects. Materials and textures
control the appearance of objects. Lights add shading and highlights to the scene. The camera provides the
vantage point for the finished scene. Let's look at each of these in more depth.
Points, Edges, and Polygons
At the heart of any model that you will create are three basic elements: points (also called vertices ), edges,
and polygons. Points represent a single location in space. The initial impulse is often to think of these as be-
ing analogous to pixels in a raster image, but this is not the case. Because a vertex represents a single point
in space, it is infinitesimally small and therefore does not appear in a finished 3D render. The fact that the
vertex is the basic building block of the 3D creative process means that it is visible only when several are
combined to create edges and polygons.
Edges make up the next level in the 3D food chain. When two points are joined together, an edge is cre-
ated. This edge now exists in one dimension and is still invisible to the finished rendering. Once again, this
should not be confused with a line in a 2D image file. For both edges and points, it is better to consider a
vector illustration without any line weight assigned. Individual points and lines may appear on the page, but
they will not print unless some thickness is attached to these elements. To see these elements, you must have
a combination of at least three of them (points and edges), which creates a polygon.
A simple triangle represents the polygon at its most basic level. Three points (with three edges connecting
them) creates a defined surface. For the most part, four-sided polygons, also known as quads , will be the
basis for your models. The reason for this will become clear when modeling is discussed in the coming
chapters, but suffice it to say that many forms can be more easily defined by quads than by triangles. By
combining and blending together multiple polygons, objects take form.
Single-Sided Polygons
Polygons exist as two-dimensional elements within the three dimensions of a scene. The flat surfaces of
polygons face in a single direction. Just as the points are infinitesimally small, so polygons are infinitely
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