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 takeoff 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 takeoff 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.
Caption: In 5D BIM, the estimator develops iterative cost plans based on the available Level of Detail in the model. S/he can see the line items in the cost plan highlighted in both the model and the budget.
Our approach derives 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 takeoff 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.
To learn more about 5D BIM, please review the following resources:
Webinar: BIM 501: Model-Based Estimating
Webinar: BIM 502: Connecting the Conceptual Estimate to the MPS
Webinar: Model-Based Estimating Basics
Product: Vico Office Takeoff Manager
Product: Vico Office Cost Planner
Product: Vico Office Cost Explorer
Services: Construction Services for Model-Based Estimating
FAQs: Frequently Asked 5D BIM Questions
We also offer a step-by-step guide to our 5D virtual construction workflow with video tutorials. These videos are just 2-5 minutes in length, but illustrate how to use a particular piece of functionality. You can access the video library index and view just what you need, or download the complete set of training videos.