While John Goodman and Arnold Schwarzenegger are both 6’2”, few would argue that they have similar body shapes. What this says, simply, is that measuring size does not necessarily say anything about shape. Even if you added other size dimensions, such as weight, shoe size, inseam length and hat size, you would still not know much about their relative shapes. Add waistline and you would start to get a sense of the difference, but from a manufacturing (or sculpting) perspective, you would still not have nearly enough information to produce either shape, or to differentiate between them.
A simple example of this in the dimensional metrology world is shown in Figure 1, where a series of two-point diameter measurements attempt to indicate roundness. While all the measurements show a nominal diameter of 1.0”, they mask various lobed conditions on the parts, which indicate actual IDs as small as 0.844” and ODs as large as 1.155”.