when you compare your scanned images (castings in my case), to a reference file, is best fitting your data and reference objects together good enough for an accurate result? do i actually need to fit planes to elements and use the 3 perpendicular planes alignment in addition to the best fit? the reason i ask, is because i have a bore that probes, and is 13.210, and my laser data when compared to cad shows its within .025 per side, or about .050 total. the nominal dim is 13.00 btw. i would pass this casting based on the laser data and end up with 0.040 machine stock, which would not be acceptable. i believe all of my alignments were very good while scanning.
What features on the casting will you be setting your machining operating up to?
it could be a boss, a centerline, or a non machined dimmension that we have to hold a tolerance to.
Best-fit and 3 pairs of perpendicular planes alignment methods are two separate functions and have no relationship to each other, you can do one or the other separately, not a combination of both.
I would suggest using Reference Points to replicate the alignment you are going to use for your machining operation.
On a side note, are you scanning into IMAlign or IMInspect?
i have only tried to use the reference point alignment once, but i will familiarize myself with it .. i am scanning into im align, then i usually reduce my overlapping layers, save it, and then open it in im inspect.