Is there a nice or easy way to get the OSM Buildings to anchor to the Terrain Height, for some reason in my project they hover over the ground by 10 meters or so. See the attachment.
Cesium OSM Buildings are placed on Cesium World Terrain. If your terrain source is off by 10 meters or so, that sounds like it might not be correctly accounting for the difference between the WGS84 ellipsoid and Mean Sea Level. Are you sure your terrain heights are accurate?
To answer your question, though, no, there’s no way to clamp Cesium OSM Buildings to terrain on the fly. The best you can do is adjust the Actor’s Z position to improve the alignment.
I will check that, I thought I had it set correctly, but could be off.