Maybe easier is to add a column to the BOM file? There should be a number of universal fields in the component description in any CAD package....
Yes, I agree a BOM extension is useful, but BOMs can get complex, and they are not always PCB-Centric.
Some are controlled from the SCH side, and others are run by SpreadSheet/DataBase managers... so getting the information into the BOM, can involve many steps and turf arguments....
My suggestion was not meant to displace BOM, just
to give a very simple means to 'sneak' Height info into standard Gerber Files.It is not as 'clever' as full mapping, but it is simple to implement for the user, and I think does not need too much software inside a viewer ?
I'll check other PCB sw for Gerber precision support. KiCad looks very good here, with 6 decimals in mm.
Addit:
KiCad defaults to this useful 1 um precision.
%FSLAX46Y46*%
G04 Gerber Fmt 4.6, Leading zero omitted, Abs format (unit mm)*
Mentor's PADS has some strange historic limit of 8 digits in Gerber, plus it internally stores to only 5 decimal digits-mm, so it can only give
%FSLAX35Y35*%
ie 3.5, which is still enough to export PCBs of 999.99mm to 99.9mm of suffix-height precision, using the 3.5 format.
I would propose that mm units be the default for suffix-height.
%MOMM*%