Several spells, or higher level spell versions, have a language like this (charm person At higher levels from the Player's manual):
Creatures should be at a distance of 30 feet from each other when you point them.
I think the above statement is equivalent to "The creatures must be within a 30-foot diameter (ie, a radius of 15 feet)."
When we play with such spells and use figurines and rugs, I and others sometimes begin to measure distances between pairs of targets, instead of simply dropping a circle template 30 feet in diameter to see if everyone can fit inside.
Am I understanding correctly, and Are the two phrases of my title exactly equivalent?
Note 1: I understand the difference between pointing to an area of effect, such as a circle or sphere, and targeting specific creatures within an area.
Note 2: Similar language appears in other editions, for example. heal mass minor injuries since Player's manual v3.5: "One creature / level, two of which can not be more than 30 feet away."