When doing foot orthotic research is that we are really clear on exactly what we want from the lab, so the preference is to use a cad/cam lab for this pupose. I often am very precise in things like arch fill (see this thread on arch fill ), and say we want, for example, 5mm on each orthotic (we need to be to control for everything in research). What I really notice is the very large differences between the left and right orthotic in their arch height when they come back.
See the rest here:
Foot Orthotic Mirroring
