Just a quick note to say Google have just removed the fee from the Google Earth Pro licence (previously $400). This has a few features that are not available in normal google earth, including some export options and the ability to record movie fly-by's and zooms. I hoped it would allow the import of 3d .kml profiles which could be viewed in through a semi-transparent terrain. Unfortunately, it doesn't. You can, however, view the 3d .kml (for centrelines) for all altitudes above 0m (sea level) as follows : Turn of the 'terrain' rendering in the 'Layers' box (unavailable in normal google earth) Open up the 'Therion KML Export' in the Temporary Places section by clicking the small arrow. Right click on the three small dots and bring up the properties box. Select the altitude tab and change from 'Clamped to Ground' to 'Absolute' You can now view a cave centreline in 3d, hovering above the aerial photography. Steve Clark