I forgot to mention, only the lower ones use the meta.
Normals in the LDraw format would be the best way to go, but like said before editing all existing parts is going to take ages, just look at the timespan BFC is taking.
For new parts the combination of >60 deg and matching type 2 lines (I think type 5 don't matter for smoothing) would be a very good and reasonable requirement.
Don't get me wrong I'm thankful to the part editors we getting all these parts in whatever form.
Normals in the LDraw format would be the best way to go, but like said before editing all existing parts is going to take ages, just look at the timespan BFC is taking.
For new parts the combination of >60 deg and matching type 2 lines (I think type 5 don't matter for smoothing) would be a very good and reasonable requirement.
Don't get me wrong I'm thankful to the part editors we getting all these parts in whatever form.