Wow, your screenshot looks amazing! We’ll connect offline to showcase your work on the Cesium website.
Are you interested in contributing your cloud implementation back into Cesium so you don’t have to maintain it? Even if you don’t think it is complete (doc, unit tests, etc.), feel free to open a pull request and we’ll help get it merged. For more info, see CONTRIBUTING.md.
As for OPAQUE_AND_TRANSLUCENT performance, it has to render the billboards twice and discard the translucent or opaque fragments depending on the pass. We knew it would be slow, which is why we waited so long to add it! There may be some optimizations for your case, for example, completely opaque billboards could be put into a separate billboard collection.
Finally, when I went to http://www.geo-fs.com/geofs.php, it appeared frozen in both Chrome and Firefox, and I had the following error in the console:
Uncaught ReferenceError: _gat is not defined
at Object.geofs.initViewer (geofs.js?kc=1490879860:130)
at dispatch (geofs.js?kc=1490879860:3)
at i (geofs.js?kc=1490879860:3)