I successfully used CTS “chop image” to create a “bump map” from the elevation source data into an 888, which is apparently the DOT3 format that is sometimes called a “normal map”.
Even a reference in the documentation somewhere that said “to create what is often called a terrain normal map, use the Chop VT with the bump map option turned on, and make sure your output format is set to 888” would be helpful.
Ironically enough, I got lots of good responses on the TerraVista page on how to do this in CTS, and a couple on the Vega Prime page, but none here. Regardless, here is a process in case anyone else is interested, posted here in the proper place on the CTS forum.
The Process to create a “terrain normal” map:
Start with the image wizard in CTS. Define your coverage to match that of your OTW virtual texture, and point to your elevation raster or DEM. Click through all the appropriate buttons and only generate the workflow.
Double click the chop process and select the “Generate Bump Map” radio box
open it up to the actual output dataset and double click it (in my case, ds4_image) and change the File Fomat pulldown to be 888 format (instead of 16 in my case). this will produce a DOT3 source virtual texture dataset
right click the “feather map” of the build_vt task in the spatial view, pull down to “Select All” so you don’t wind up feathing our the edges of your map.
leave build alone, and you can bypass the convert task.
Run the workflow. You finished, filled, normal map VT should reside in dsN_image_common_vt if you haven’t changed the names, in my case N=6, but that would change if you use multiple resolutions of terrain DEMs, start at a different number, or have different stuff in the middle.
Whatever you do, do not go out and purchase DOT3 brake fluid and pour it onto your keyboard - it will start to eat the little rubber membranes inside 8*); this will NOT give you a DOT3 normal map.
