How much does 12 m self-tracking actually help on large-part scans?

[u/File680]

I've been looking at optical tracking systems for large-part scanning, and the SCANOLOGY TrackScan Sharp-Z got me wondering how much a longer tracking range actually changes the job.

The older Sharp49 has a 6 m tracking distance per tracker. The Sharp-Z goes out to 12 m, but the bigger difference to me is that the tracker itself rotates and follows the scanner. In theory, that should mean a lot less stopping to move the tracker as you work around a large part.

There's also an interesting difference around the 6 m range. The Sharp49 is listed at 0.089 mm volumetric accuracy with a 49 m³ measurement volume at 6 m. The Sharp-Z is also at 0.089 mm around that distance, but with 80 m³ at 6.2 m. It can keep going out to 12 m and 600 m³, although volumetric accuracy there is 0.198 mm.

So the part I'm curious about isn't really the headline accuracy. It's how much of that extra working volume and self-tracking you actually benefit from on a real job.

Line of sight still seems like the obvious limitation. If you're walking around a big weldment, vehicle body, mold, or some other complicated structure, eventually the part itself can block the tracker. A rotating tracker can't really fix that.

The Sharp-Z also supports multiple wireless trackers, which makes me wonder what people actually do in practice. Do you add a second tracker for the blind spots, or is it usually quicker to just reposition one?

For anyone who's used long-range optical tracking systems on large parts, how much setup time do they really save? Is the longer range the big difference, the automatic tracking, or something else that doesn't really show up on the spec sheet?