Abstract: A method of determining a spatial hierarchy for polygon data, comprises obtaining a switching range, and determining a polygon density for the spatial hierarchy, using the switching range and a cube-root scaling factor. Another method of determining a spatial hierarchy for polygon data, comprises determining a cube-root scaling factor based on an altitude parameter, and using the cube-root scaling factor to scale level-of-detail switching ranges for the spatial hierarchy. The methods may be embodied in a computer program (or some unit of code) stored on a computer readable medium, such as a compact disc (i.e. CD), and/or transmitted via a computer network, such as the Internet, or another transmission medium.

Abstract: A flame suppression cabinet for printed circuit boards includes intumescent material that expands at an elevated temperature to block ventilation openings in a top panel. Fire suppression plates are positioned between adjacent ones of a plurality of printed circuit boards positioned vertically on a shelf rack in side-by-side spaced-apart parallel relationship to prevent fire from spreading between the circuit boards.