One of the fundamental modules in D5 supplies a model of the earth (or other, roughly ellipsoid planet) to the core representation of the DIRSIG universe. The distributed version of D5 will likely contain a simple, material-mapped sphere representation of the earth by default (to keep download sizes reasonable), with the option to obtain more detailed (and more correct) models. To this end we've been working on an earth model based on the WGS84 reference ellipsoid and SRTM ( Shuttle Radar Topography Mission ) DEM data. Since this is a very large data set (the 500m data we're using currently is 4.7GB in its raw form) it is an ideal case to test some of our new large file handling routines and integrating them into geometry interactions. We model the earth as a collection of triangle mesh patches representing cells (primarily hexagons) of a geodesic, specifically the ISEA aperture 4 resolution 7 grid (i.e. 163,842 index cells). Each patch can be loaded into memory independently, ...
A blog about the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model featuring posts contributed by the developers. This is not a user manual and it is not a training class. But, it is a place to see what the developers are doing and a little about how we do it. So think of this as a place to learn cool tips, tricks, etc.