A live model

Kiln Hall’s pipe drawing is from 1998. A plumber moved a run in 2014. The paper did not move.

A drawing is a guess frozen on the day it was drawn. A live model is different in one way only: when moisture or flow changes in the real building, the model changes too, and someone who can act is told. If nobody updates it, a live model becomes a drawing again.

You can still be wrong. Then you learn whether the model was stale or the pipe really failed. Both answers are useful. A flashlight walk after the plaster has fallen is late either way.

Once you see the difference as “kept honest by measurements,” a pretty 3D picture of the hall stops looking like a twin.

The tempting mistake is to mistake a nice picture for a live model.

That is what lets you ask who runs one of these today.