I'm assisting a fabrication client with digitizing steel forming rolls using 3D scanning, and so far... we have been getting some weird results from a structured light scanner (Artec Spider). The surfaces come out a little warped and the dimensions are off by up to 0.8 mm from hand measurements. I know it's technically not much but it's not acceptable for precision work. It's not accurate at all, too. I'd appreciate a breakdown of pros/cons between structured light, laser, and photogrammetry in terms of accuracy and repeatability. We're working on cylindrical parts so it would be best if you have some tips specifically for those.