Does anyone know how to build something similar to this with TouchDesigner?
Hello,
Yes I have done it in two occasions.
– one with kinect and at that time with Isadora and Processing (GLSL shader) easely adaptable to TD. (thats not sand but body)
– one is without direct interactivity, using bathymetry, a PS4 joystick to move and point cloud to vizualize. Using GLSL shader to colorize points depending on depth.
(at 9’08“ left screen)
If I have time, I will make a tuto 
Thank you!