@Medix2 no, TM retagged the two questions - one that I tagged and one that Trish tagged to the 3d-space tag. The initial tag related to Trish's answer here
rpg.stackexchange.com/a/185125/44723 - TM retagged the two questions from the volume tag to the 3d-space tag. Before TMs retags, the tag usage was for movement and calculating movement in a 3d environment. For some reason, TM took the "calculations" part to mean volume as well.