Hi all, I have Geotiff data for both DEM and Images (for texture) which are large volume files (>500MB each). I am trying to write an IDL program able to deal with such large volume data. Basically, I load the data with READ_TIFF() and use a Graphic Object ("IDLgrModel","IDLgrSurface",...) for the 3D visualization.Unfortunately, I often get Memory error, and then if the data are displayed, "flying over" is just too slow. I have a pretty decent PC (DELL Precision Workstation) running IDL 7.0 with Red Hat Linux 5 and NVIDIA drivers are also installed. Is IDL not enough powerful to deal with such kind of large volume data? thank for any feedback