Apples to Oranges: Comparing BIM Scope

BIM&ConstructionTechnologyAre you trying to estimate the cost of virtual design and construction services on your next project? Does the estimated cost of BIM vary significantly from project to project and from bidder to bidder? Managing the following variables in the preconstruction process can help you compare BIM scope as apples to apples as opposed to apples and oranges.


BIM is clearly defined as Building Information Modeling, but the clarity in comparing BIM on one project to another stops at the definition. There are variables that can significantly influence the cost and schedule of BIM on a project. Communicating without clarity can lead to large variances in the estimated cost of work. In order to understand the cost of BIM and ensure that bidders understand the scope similarly, consider these variables on your project:

  • BIM Execution Plan: A well written BIM execution plan can provide all the pertinent information to plan and execute a project often in fewer than 5 pages. It will clearly set coordination rules of engagement, meeting frequency and structure, and expectations regarding the detail of the model.
  • Software Coordination: Defining the acceptable software formats to be used for coordination is critical to developing a cost of work. Minor changes in versions or platforms can create time consuming problems for trade contractors. Changing versions after coordination has started should be a last resort and only pursued if there is buy in from the entire team.
  • Coordination Responsibilities: Tasks such as hosting meetings, managing models and file share sites, or providing clash detection reports can increase cost. Spelling out who will be responsible for each of these tasks at the preconstruction stage will help insure that estimates cover the same scope. When identifying responsibilities, it is important to identify all of the participating trades in the BIM coordination. Bringing a trade contractor on-board late is very disruptive. Late involvement leads to re-work and/or inefficiency in system coordination. It is the CM/GC’s responsibility to ensure all parties required for the coordination are engaged prior to embarking on the BIM coordination.
  • Coordination Details: Scope related to coordinating with existing systems, providing hyperlinked submittal documentation, or modeling and coordinating in-wall services can drive costs up or overlooked if not spelled out in the bid documents. Determine how the team will model code and manufacturer’s suggested service clearances. Don’t leave this up to industry standard LOD (level of development) definitions.  Often these definitions are insufficient to accurately estimate a project scope.
  • Construction Drawings/BIM Deliverables: Deliverables vary from project to project and need to be identified up front to assess the scope. Identify if and where the BIM can be used to supplement or replace traditional deliverables. Identify what drawings will be required by the construction team.


Providing this information to the team early and consistently will provide better feedback and a more complete scope so you can compare apples to apples.


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About Dan Cotton


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Dan Cotton is the manager of Virtual Construction at McKenney's and is responsible for our BIM and CAD modeling teams. He has been a member of the LEAN Construction Institute (LCI) since 2011 and is currently a core team member of the LCI’s Georgia Community of Practice. Dan holds a Six Sigma Green Belt certification from Georgia Tech and led the LEAN efforts at McKenney's from 2010 through 2013. Prior to his involvement in Virtual Construction and LEAN, Dan was a project manager in the McKenney's New Construction division for six years.

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