Height maps change vertical offset character animations (avatars) are rendered at. The change is to the animations themselves, and not to the footcircle of the animation, i.e. avatars move vertically within their footcircle. The change is relatively subtle - the maximum and minimum values are demonstrated in the image below - pure white is on the left, and pure black is on the right.


The palette for a height map is 4-bit (16 colour greyscale). A sample height map (from ar0072) can be seen below.