Graphics Reference
In-Depth Information
world, we would all have massive banks of computers to do our digital bidding, and a brute-force method
would get the job done, but in our world we will have to settle for being smart.
Two main issues affect the quality of a rendered image: pixel quality and lighting quality. Each of these
has its own set of specific problems, but it really all boils down to those two things. Occasionally, there is
overlap between the two, but more often than not, one of them is the culprit that keeps your image from
looking its best.
Improving the Quality of Rendered Pixels
Often, images show jagged or oversharpened edges in areas of high contrast. The answer to this problem
is
antialiasing
. When straight lines are created in digital form, they can be properly represented only hori-
zontally or vertically, because the pixels on the screen are square. Any line angle other than that has to be
represented by the stair-stepped look of jagged pixels. The addition of transitional pixels in the gaps between
the stairs helps soften the look. In a 2D application, simply blending pixels does this. In 3D, there is a dif-
ferent approach. If an image has areas of high contrast at places where this jagged look appears, antialiasing
kicks in. The offending pixels are rendered at a higher resolution; the result is then scaled down to derive an
average, which is displayed as the finished pixel. This would be the equivalent of having additional resol-
ution levels of an image or photograph and, where needed, a higher resolution could be sampled to smooth
out the jagged edges and create a refined image. Anyone who has spent time rebuilding a client logo from
an enlarged photocopy of a 12-year-old inkjet-printed business card can greatly appreciate this.
Fortunately, as long as the original model files are kept, 3D renders always exist independent of resolu-
tion. For this reason, you can always draw from a higher resolution or “retake” the original long after the
project is completed. This is one of those amazing benefits to adding 3D into your workflow. Let's start by
taking a look at a render from the previous section with no antialiasing (see
Figure 7-31
)
. As you can see
from the enlarged section, there are lots of stray pixels and jagged edges.
Figure 7-31:
A rendered image with no antialiasing
