Appreciate the response.

One thing I've struggled with in threejs is what coordinate system to use when pulling in data sources. Obviously UTM and lat/lon are inappropriate when you're dealing with a slice of terrain in 3d like this, and from my experience using the 1x1 unit tile dimensions of something like a web maps tile coordinate system does not play nice with ThreeJS at all.

Do you just project to Mercator/Web Mercator and then arbitrarily pick something like 1km = 1000 units to work with the data in ThreeJS space, or is there some kind of an established coordinate transform that is commonly used when bringing geospatial data into a non-projected xyz coordinate system?