We followed the same protocol at rectangular areas measuring ... including the complexity of reef structure across large areas. By comparing the 3D models, we can see how complex the surface ...

Enter the Structure Sensor ($380), a gadget that turns your iPad into a 3D mapping and imaging device. You can use it to measure the depth of a room or create a 3D model of an object or person.

Since then, centuries of looting reduced the formerly breathtaking building to scattered ruins, but scientists recently restored the enormous structure to its former splendor — as a 3D model.