As always, these are just introductions and overviews, not legal advice. If you have specific questions, or need a new contract, talk with a lawyer. I am a Massachusetts attorney and I default to Massachusetts law; some of the information in my blog posts will inevitably be incorrect in other places.
BIM Used By the Design Team
I’ve heard this described as “Stage 1 BIM”: The BIM model is only for the use of the design team. The team creates the model and uses it to generate printed or PDF drawing sets, which are the deliverable.
In the least BIM-coordinated version, the architect develops the BIM model uses it to create PDF drawings and two-dimensional CAD underlays, and transmits those to the consultants (the engineers, interior/landscape/lighting designers, cost estimators, etc.) The consultants use those files in combination with their software of choice to produce their parts of the drawing sets, which they transmit back to the architect as more 2D drawings. Coordination between the disciplines is done in 2D, on paper, and whatever changes result are made by each discipline.
In the more coordinated version, the architect and the consultants use compatible BIM software packages - for example, Revit Architecture, Revit Structure, and Revit MEP (which are now a single product with different interface options). The architect creates a main building BIM model and transmits it to the other team members, with updates provided on a schedule, and each team member can build on the model, for example by adding structural elements, ducts, plumbing or lighting, to data sets that can be maintained separately but loaded and viewed along with the main building model.
More Coordination = More Uses + More Complications
By extending the use of the BIM model to the consultants, the design team can improve coordination between the disciplines, and can more quickly and thoroughly check for conflicts between building elements. For example, it is easier to see where a duct does not fit between a beam and a recessed light when the duct, the beam and the light are all in the same 3D model. When each of these components is modeled with a certain degree of dimensional accuracy, some software packages will automatically detect such conflicts and display them to the designers. Drawings can be generated showing the different elements in relation to one another, and lists of all included building components can quickly be produced for cost estimating.
With this power comes the need for new coordination between the disciplines, and new contract language. This is where the BIM Protocol comes in. A BIM Protocol is a formal description of the obligations of each team member in creating the BIM model:
- What components each team member will produce, to what degree of detail and on what schedule.
- What team member maintains the file repository and in what form.
- The schedule of model file updates and coordination meetings.
- Copyright licenses governing use of various team members’ BIM models by the other members.
- Assignment and limitations of liability.
- Identity of the BIM manager, who is responsible for coordinating the BIM project across disciplines.
Currently many or most design teams that use BIM models use their BIM software to generate 2D drawing sets, which are the client’s deliverable. The client and contractors only have access to the drawing sets, not to the BIM model itself.
Many contractors now use BIM models in their process, in systems that improve coordination and scheduling and monitor progress between trades. Some contractors, when provided only paper drawings, proceed to generate BIM models from the drawings or contract with drafting companies to have models produced. Later, when the building is complete and occupied, the owner’s facilities manager might use a BIM file as part of a system for monitoring building performance and diagnosing building systems problems.
Logically, the next level of BIM use is the BIM deliverable. When the design team provides a BIM model to the contractor and owner, they save the work of making a new BIM model and opportunities for translation errors are reduced. But BIM deliverables require a further elaboration of the BIM Protocol, and very clear contracts that set the expectations for BIM model accuracy and completeness and govern the permitted uses of the model by each party.
In my next BIM Law post I will discuss BIM contracts and the array of expectations they must manage.