BIM Presentation by Noel Susskind, PE page 2

3. 2D drawings are being superseded by BIM

The traditional Design-bid-build procedure has worked for 200 years, why change now? Much waste in the form of duplication occurs in the construction business. Duplication of labor, information, and so on.

Compare the productivity index of the construction industry to all non-farm productivity.
Construction productivity chart

Competition is fierce and more and more information is necessary for contractors to bid effectively. Pressure to reduce, if not eliminate, mistakes (and the inherent financial losses) is high. In fact, drawings and specifications are viewed as risk controls as much as a contract documents.

Ed Goldberg, noted architect /author said: "the construction industry … is organized around the mitigation of risk. Big bucks are involved when an owner and contractor commit to a project…"

A little history: Traditional methods for Construction Documents are 2d drawings Construction contract documents have traditionally been the plans, elevations, details, and so on. Drawn plans go back thousands of years. Construction drawings were probably well in use by the time of Vitruvius in the 1st century AD. (There was a lot to keep track of in building Rome)

Vitruvius

Building systems like lighting and HVAC were once an afterthought and they often didn't appear on construction drawings. Architectural and structural plans were all you got in 1925, but if you were lucky, you might get a drawing showing piping to steam radiators. But the drawings were sufficiently detailed for contractors to bid and build. Litigation was less common then.

Sophisticated building systems, like HVAC, plumbing, electrical, life safety and communications systems, were only added more recently. Building information that is not on the drawings was specifications or some other text.

Drawings have never had every detail necessary to describe everything the contractor needs to fabricate and install. That was the preserve of shop drawings.

Construction drawings, for example, show a ducts location and dimensions. One would not usually build ductwork from these drawings. The information therein is usually converted to a shop drawing. The shop drawing gets a conditional nod and approval from the designers, then the contractor commits to the executing: materials acquisition, assembly, mounting, and so on.

Contractors have traditionally taken the drawings to be approximately correct as to dimension, quantities, and so on. Then shop drawings are created, then checked by the designers of record in order to confirm intention and methods of execution. Each part of the project is checked to make sure things fit. Discrepancies in the design that lead to expensive changes, et al, are resolved in ad hoc fashion during this process. An entire industry of project management firms have developed around this process.