Computer-generated backdrops - 3
Terragen is to reverse-engineer examples provided by the user
community. A number of websites, including Planetside’s, pro-
vide examples you can download to help you learn the craft.
Despite the challenges, the quality of the simulations is quite
striking and well worth the effort.
All the world’s a... fractal
The core of all terrain generation software is a class of math-
ematical functions called fractals. In very loose terms, fractals
recursively generate data that is self-similar but at a different
scale. We see examples of self-similarity in nature. A hill is a
smaller version of a mountain, a rock has similarities to a hill, a
grain of sand has similar characteristics as a rock, and so on.
It turns out that through this characteristic of self-similarity
and the insertion of specialized randomization functions, one
can very realistically simulate patterns found in nature includ-
ing the terrain of a mountain, vegetation on a hillside, and even
clouds in the sky. Virtually every element of Terragen is layer-
ing the effects of multiple fractal functions to create a virtual
model of a 3D scene.
While it may be helpful to understand fractals, luckily that is
not required. When someone asks how a computer can create
such realistic images, simply answer, “fractals, of course.”
Scene development
There is no way to convey all of the details required to become
proficient with Terragen in this article. My objective is to convey
the basic process and demonstrate the possibilities.
The overall process of building scenes in Terragen is as follows:
Establish the bare terrain
Position camera
Shade terrain
3. Image stitching software is used to combine
computer-simulated images to create the 17’- long
backdrops for my double-deck shelf layout. Images
were printed on special commercial wallpaper stock
that I hung as a single image with no seams, using
wallpaper paste.
MRH-Jul 2014
