
10
Shape-Preserving Terrain
Decimation and Associated Tools
David Eberly
10.1 Introduction
I worked on a truck-racing game with large terrains, each level approximately 3 miles
by 3 miles in size.
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The game shipped on Xbox 360 and Playstation 3. Level artists
initially created each terrain as a height field by painting a 2K-by-2K, 16-bit TIFF
image, each texel value representing the terrain height. A regular tessellation of
the grid using two triangles per texel produces 8M triangles, which is too many
triangles to draw per frame. We wanted a decimation algorithm that would give
us a greatly reduced number of triangles yet still preserve the general shap ...