Glad to hear you like what you see in Cesium so far!
The terrain data hosted on cesium.agi.com is a processed version of the SRTM data from CGIAR . I processed the data using GDAL’s gdal2tiles.py script , which I modified to generate TIF files instead of PNGs. I then converted those to PNGs with the Cesium height encoding technique using custom code adapted from the “proxy” project in the Cesium tree . You can follow these same steps to produce the data yourself if you’d like.
As you may know, I work for a company called AGI , as do most of the other current Cesium contributors. AGI is currently hosting a public terrain server with this data for free, and will continue to do so for for the foreseeable future (if I get my way - I can’t promise it, of course). However, we will also sell a terrain server pre-loaded with the data for use on private networks, as a means to offset the cost of acquiring, processing, and hosting the data publicly. So that might be an option for you guys down the road.
In the meantime, though, I have no problem with you caching a bunch of our terrain tiles locally for demos. The entire dataset is 7.5 million tiles, so please don’t download the whole thing. But feel free to download a few tens of thousands of tiles comprising the globe at low detail and an area of interest or two at high detail.
I hope that helps,