I've been playing around with a web-based tool for adding 3D primitives for rendering in edWare 3D. In an HTML form, the user can enter values for transparency and color; location can be entered or selected from a map view. By default, elevation is set to DEM elevation at the selected location, although the user can enter whatever elevation they'd like. I'm particularly fond of spheres:
(Click for higher res version)
So you can see some different locations, color and transparencies. A bit ho hum...
Then I thought it might be nice to form a line in "string of pearls" fashion:
http://www.ctmap.com/serendipity/index.php?/archives/2-Fog-at-Staunton-State-Park.html