Surfaces or Wall Dimension Layer?

[HumbleChief]

I'm usually not too picky about absolutely perfect dimensions because most of my work is small residential remodeling with restrictions and tolerances placed within the original home's dimensions and a lot of true exact dimensioning done on site. I'm now in the process of designing a new home and know how dimensional errors or inconsistencies can really add up along a very long wall and larger interior spaces so my question is what do you dimension to?

'Surfaces' which I assume is drywall/stucco/siding and seems to make no sense for a framer or 'Dimension Layer' which I assume is the main layer or framing. Seems pretty obvious on the surface but wondered if there's something else I should know?