status of vector data on terrain, polygons clamped-to-ground?

May i ask, what is the status of vector data on terrain, polygons clamped-to-ground?
I was looking fwd to this in March, then April, and now it's priority seems to have dropped down off the radar...
my avalanche forecast Cesium map for the USFS Mt Washington Avalanche Center is dead in the water, as far as 3D view, until I can clamp geojson polygons to terrain, and now avalanche season is over...
Thanks for any info you can provide...
Jon Hall

Hi Jon,

Wow, cool app, can you share a link?

Vector data on terrain is still a priority for Cesium, the timing is because a solid implementation is non-trivial. Labels/billboards are almost ready, see the globe-depth branch. Polygons are also almost ready but have some challenging corner cases we need to figure out. See the ground-primitive branch. These low-level graphics features will also be wired into the Entity API (and therefore the GeoJSON loader), see the entity-clamp-to-ground branch.

If you want to experiment, you could prototype something off of these branches, but I wouldn’t use them for production work yet.