The third point in the design-to-construction trio, alongside As Made and As Built. The As Designed model is the design team's original intent - what should be built, based on the design decisions made before construction started. It is the baseline everything else gets measured against: As Made captures what was actually installed on site, As Built is the coordinated record of the completed building, and the gap between As Designed and As Built is, in effect, a map of every change that happened during construction.

Keeping the As Designed model intact, rather than overwriting it with site changes, matters for exactly this reason - without it, there is no way to see how much the finished building actually diverged from the original plan.