Tech Report CS-05-14

A Heightfield on an Isometric Grid

Morgan McGuire and Peter G. Sibley

October 2005


A Heightfield on an Isometric Grid

The iso-heightfield is built on a grid with 60 degree-axes that produce an equilateral tessellation, which is the closest packed regular tessellation. We design a grid- to world-space mapping that is convenient for triangle strips and provides square tiles for level of detail and texture management. This makes the iso-heightfield an efficient drop-in replacement for the orthogonal heightfields commonly used today. We introduce several new support algorithms including fast vertex normals and self-shadowing. The iso-heightfield requires resampling when data was previously captured from an orthogonal grid or irregular samples. This is a lossless process if the original sampling filter is known and the Nyquist rate was observed.

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