A drawing is a frozen instruction set. So is a fabrication spec. The two artefacts have different audiences and different conventions, but they are doing the same job: telling someone how to make a thing.
In the conventional pipeline these documents are written in different rooms by different people, then reconciled. The reconciliation is the source of most errors and most rework.
We treat the architectural drawing and the fabrication spec as two views of the same model. Change one, the other updates. The line between them is, increasingly, a fiction.