The first thing you want to do is set up an appropriate base plane equation by running calibration step 4. All elevation values used by the AR Sandbox are relative to this base plane. Say your Kinect is 50″ above the flat sand surface, then the offset value of your base plane should be about -127 (cm).

If you want to adjust elevation ranges (surface min/max and rain layer min/max) based on your local setup, you can use KinectViewer to measure the 3D coordinates of arbitrary points on the surface, just as you did for the box corners in calibration step 5. Those values will be in camera space, i.e., to convert them to base-plane relative elevation space, you need to subtract the base plane offset. Say you measure the top of a high mountain at (30, -20, -86), i.e., at a z position of -86 relative to the camera, then that point’s elevation above the base plane is -86-(-127)=41 (cm). That would then be the number to use for max elevation, and so forth.

If you download the new Kinect-2.8-001 and SARndbox-1.5-001 packages (see Two minor software updates), you can take these measurements more easily directly inside RawKinectViewer. See the new calibration video linked in the complete installation instructions.