Second-hand depth cameras (an Intel RealSense SR305, the D415 hiding inside a Prowise MOVE 3in1) see depth 30 times a

second for the price of a takeaway. Turning one into a 3D scanner is easy right up to the point where you line the

frames up. Then the object grows a second nose.

I'm working on about 50 projects at once, so I don't have the time or brain capacity for humour; it cuts into my four

hours of sleep-eating time (efficiency). So, straight to it, apart from the title: Icy Ewe (say it out loud) is the write-up of how my app,

Scantastic, keeps a scan together on bad cameras and slow computers:

Picture features check every step the 3D shape suggests, and veto it when the shape is fooling itself.

Loop closures can't lie: one the pictures can't confirm may only move a frame as far as the chain could really have drifted.…