Defining the Scope of BIM

by Michael Tardif, Assoc. AIA
Contributing Editor

Summary: With building information modeling (BIM) becoming more and more common as the preferred platform for building design and construction, the content of the model looms larger as the subject of negotiation between business partners. BIM fosters greater collaboration through digital information exchange, but the near limitless possibilities for design detail in BIM means that the parties to any exchange need to define the limits, or scope of the model, for any particular project. Owners are increasingly specifying BIM deliverables in their RFPs, but the scope of work, or “level of detail” of the model is rarely indicated with any specificity. This creates an environment that could, at best, lead to misunderstandings and, at worse, lead to contractual disputes.

Design firms that implement BIM encounter this problem very early in their implementations. Design teams have to decide on every project which elements of a building should be modeled three dimensionally and to what level of detail. For some elements, it may make more sense to represent them in conventional 2D form with an object “tag” that is tied to alphanumeric information within the model about that object. Plumbing fixtures are a good example. It simply may not be worth the trouble of creating or inserting 3D models of toilets in a commercial building model when a 2D symbol that displays correctly both in plan and elevation would do the trick. It’s more important to include in the model the alphanumeric information about that object—the manufacturer’s name and model number—than it is to display its geometry. The important thing to remember is that a BIM is intended to be a building information model, not a building geometry model. The goal is to capture all relevant information so that the information model can fairly be described as an accurate virtual representation of the building. That does not mean that every single detail of the building must be represented geometrically.

This problem has been recognized for some time, and over the last few years, as the building industry has developed more experience with BIM, significant efforts have been made to address it. This is very important, because unless business partners can agree on the scope of a model, a BIM-based project is not likely to be as successful as it could be.

A case study in collaboration
The story of how a solution developed is a case study in collaboration that is as important as the solution itself. VICO Software began developing what they called a Model Progression Specification (MPS) in 2004, which led to collaboration with Vico customer Webcor Builders. This brought Jim Bedrick, AIA, of Webcor Technologies into the process, a fortuitous occurrence. Bedrick leads Webcor’s efforts to implement innovative technologies and is actively involved, as an AIA member, in advancing the technological sophistication of the architecture profession and the entire building industry, both on the state level with the AIA California Council (AIACC), and at the national level with the AIA Technology in Architectural Practice (AIA TAP) Knowledge Community and the BIMForum of the Associated General Contractors of America. Sitting at the nexus of all of these organizations, Bedrick became the conduit for knowledge transfer that allowed this work to be rapidly disseminated throughout the industry.

The conduit for knowledge transfer allowed this work to be rapidly disseminated throughout the industry

The MPS initially developed by Vico and Webcor was eventually published by AIACC’s Integrated Project Delivery (IPD) Task Force as a public-domain spreadsheet on a dedicated IPD Web site, where it is still publicly available for download by anyone who wishes to use it. The effort was next picked up by the AIA Contract Documents Committee, resulting in the publication in November of last year of a new member of the AIA Contract Documents family, AIA Document E202-2008, “BIM Protocol Exhibit.” This new contract document incorporates the MPS with only minor modifications as the “Model Element Table” and wraps it in formal contract language that allows E202 to be incorporated into any AIA Owner/Architect agreement by reference.

A project decision guide
The salient features of both the MPS and E202 is an expandable, prescriptive table of building elements based on CSI’s Uniformat and five defined “levels of detail” (also user-definable) for each building element. The value of these documents is that business partners can sit down, ahead of time, and decide what building elements will be included in a model, to what level of detail they will be developed, and who will be responsible for developing them. These documents are, in essence, “BIM scope definition documents.” Architects, in particular, can use either document to take the lead in negotiating the scope of a BIM for any project, which will benefit them in three ways:

• Demonstrate to clients a very sophisticated knowledge level of BIM
• Educate clients about BIM scope issues in a non-confrontational way
• Help reduce ambiguity (and therefore risk) about the scope of BIM deliverables.

An object lesson in the type of collaboration that is at the core of integrated project delivery

As this useful negotiation and scope definition tool developed, each player in the process—Vico, Webcor, AIA California Council, and the AIA Contract Documents Committee—exhibited a culture and attitude of information stewardship rather than information ownership. All focused their efforts on disseminating knowledge that could benefit the building industry as a whole, rather than protecting their own turf or serving their own interests. It is an object lesson in the type of collaboration that is at the core of integrated project delivery and a hopeful harbinger of the future.

For more detailed information about the development and content of the MPS and AIA E202-2008, see the excellent article written by Jim Bedrick published by AECbytes on September 18, 2008.