March 25, 2008 

Recently, I attended a teleconference organized by the Association for the Advancement of Cost Engineering (AACE). The purpose of this call was to kick-off an effort of the AACE's BIM Technical Committee to define requirements and standards for the use of Building Information Modeling for quantity take-off and estimating. Among the participants were owners, contractors and universities, all eager to contribute to this project.

The start of this project is an important and highly interesting development in the adoption process of BIM in our industry. However it is evident that Building Information Models implicitly contain a large collection of project information, which is captured by means of CAD objects, a lot of this embedded information is not directly available for users to, for example, create model-based estimates and schedules. Clearly defining the real needs from BIM for estimating (and scheduling) will therefore proof to be crucial for a successful adoption of BIM for construction.

Of the set of model-based information that is directly available for BIM users, now even through (semi)direct connections to estimating software packages, only a sub selection is useful for estimating. Regretfully, the Level of Detail (LOD) of this information (typically existing of square footages, numbers of elements and volumes) makes that the usefulness of the extracted BIM data is basically limited to estimates in the conceptual and early design phases.

Of course, the question "what can be expected from a model-based estimate?" arises.

The answer is: it depends on the LOD of the model-based quantity take-off and how well requirements are documented.
In the projects that we at Vico have worked on over the years, we have identified a set of quantities and element attributes that are required for detailed estimates and schedules that go beyond the conceptual and early design phases.

Vico products derive the available information from the Building Information Model and then process it in such a way that cost and duration of construction activities such as formwork, finishes and MEP, which require more specific quantity take-off input with a higher LOD, can be based on that model. The set of integrated model data that is created the Vico way can be used from conceptual phase to construction, making BIM possible throughout all project phases for estimating and scheduling.