Its datums contact the functional datums of the gauge. The virtual condition is illustrated in VC1.1 in the 3D Virtual Condition section. In the same section, also refer to Figure VC1.3, which shows the shaft and hole virtual condition boundaries superimposed and thus demonstrates guaranteed fit. Parts that mate perfectly despite rough surfaces, fabrication and inspection at different facilities, and handling-induced changes to dimensions before incoming inspection. In summary, we have seen how GDT functional gauges designed according to virtual condition ensure part fit.
Virtual condition is the envelope for worst-case part fit.
A part which fits on such a functional gauge is guaranteed to fit to all mating parts.