Thinking out Loud:
I can not express the importance of field verifying dimensions. It is important for contractor to field verify prior to construction or fabrication, but it is also important for architect to field verify before they start drawings. I have heard the horror stories of an architect designing a high end corporate headquarters in an existing building, but not field measuring the space. I don't know exactly what he based his floor plan on, but instead of the column being on the corridor wall in the hallway, it was about four feet inside the CEO's office. This is not a good situation.
If an architect is going to work in an existing building there are certain situation that he needs to field measure the space.
1) The obvious situation is when there is no existing plan.
2) If he is provided a print or PDF he may need to go verify
The only exception is when he is provided a CAD drawing by the client. We assume the client has had someone else go out and field verify the dimension, so unless specifically asked to go verify dimensions, if you have a CAD drawing it should not be ne
A self employed architect. Office of one.