A neat new feature! Thanks! However, I am reminded of the old adage - A man with one watch always know the time. A man with two watches is never sure. Using a rather simple 50 meter cave as an example, I now get four different calculated volumes. Three of them are at least in the same ballpark, but one is about three to four times greater than the others. Compass = 5931.1 cubic feet Loch LRUD volume = 3754.1 cubic feet Loch Maps 3d = 6106.8 cubic feet MeshLab = 586.9 cubic meters (20697.9 cubic feet) MeshLab is an outlier here. ======== Bill Gee