I am displaying a 3D polygon layer in ArcGlobe based off of floor levels(minimum height above ground) and ceiling(maximum height which im extruding by) from a 30m DEM...no problem since it based off of Above Ground Level. I'm trying to figure out how to display other 3D polygons whose floor and ceiling levels are based off of Mean Sea Level. Is there anyone that know how to convert or what I need to do to achieve this? Ideally I want to be able to visualize overlaps in the 3D polygon based off their MSL and AGL ceilings and base heights. Thanks so much for assisting.