(released August 29, 1997)
I spent a year or two working on issues relating to terrain simplification. The result was a paper and the Terra/Scape programs. However, I moved on to broader simplification issues. In particular, I focused on simplifying arbitrary polygonal models. The result of that research was the QSlim simplification package.
I have not done any real development on my terrain software since January 1996, and I am unlikely to have any time to work on it any time soon. However, I have made a few small improvements now and then.
The newer QSlim package is based on my quadrics-based simplification algorithm. For any given terrain data set, the QSlim software is likely to be slower and use more memory than the Scape software. However, it is also likely to produce a higher-quality approximation. And of course it can also simplify a much broader range of surfaces: it can process any triangulated surface rather than just a regular grid of height samples.
The algorithms used in the Scape software package are described in the paper Fast Polygonal Approximation of Terrains and Height Fields, by Michael Garland and Paul Heckbert.
Errata: The figures of Crater Lake incorrectly show the actual terrain flipped upside down.
A related paper, Survey of Polygonal Surface Simplification Algorithms, by Paul Heckbert and Michael Garland, is also in the works. At one point, this was a companion paper for the one above which focused on various algorithms for terrain simplification. However, it has since evolved into a more general survey of surface simplification algorithms. The most current version of this survey was published in the SIGGRAPH 97 course notes [PDF]
The most recent version of Scape is version 1.2. It was released August 29, 1997. Scape is distributed in two pieces:
The following changes were made in Scape 1.2:
The following changes were made in Scape 1.1 (released January 17, 1996):
In December 1995, I started working on an improved version of Scape, called Terra. This software is easier to use and easier to understand. The code is cleaner, and it actually supports some useful features that Scape does not.
Terra was never actually finished, and I haven’t had time to work on it for the past year. However, it should prove quite usable. You can find more details in the current documentation for Terra. If it sounds interesting, you’re free to download the last snapshot of Terra with the understanding that it is unfinished and may never be finished. You’re free to use it, but you use it at your own risk.
I have the following software available for download: