Destroying the curve

So you’re feeling pretty good about the rodent virtual reality system (Hölscher et al. 2005) you have up and running. You’ve got it all… the spherical treadmill with motion tracking feeding back into a 3D vector graphics program that projects a first person view onto a spherical screen. It’s a complex system to put together, no doubt. You deserve to feel proud.

Then Lukas Fischer comes along and destroys the grading curve.

Lukas’ blog is a detailed diary of his meticulous design and engineering work as he assembles his mouse VR rig. In addition to narrating the design and fabrication process, he draws raytraces for the optical projection in his CAD illustrations, like so:

His final work resembles the CAD drawings remarkably well.
Theory:

Reality:

He came up with an elegant solution for the spherical treadmill. After an apt dig at over-engineered approaches:

Different techniques have been used in the past to get a good cup for a 20cm or 8in ball. […] UCL carved it out of a solid block of gold (or so I can only assume given the pricing)

Indeed, UCL’s expensive (about $5700) spherical treadmill, albeit nicely made, is no where near as efficient as Lukas’ solution: a polystyrene sphere inside another, slightly larger, polystyrene hemisphere with air jets. (link, link)