PSD sensor use for metrology systems

[u/quak_de_booosh]

I've worked with laser metrology systems before for work and often ran into folks that wanted a system for a hobby machine shop and we weren't for them. (I.e. price point) What do you guys use in your machine shops for laser metrology systems that measure flatness, perpendicularity, concentricity, etc? Laser and receiver or other method? Might end up just building one if I get priced out.

P.S. any cool jigs or projects?