Estimators and general contractors should understand how BIM can support specific estimation tasks, minimize errors, and improve the accuracy and reliability of cost estimates. More importantly, BIM enables a swift response to critical project phase changes—an ongoing challenge many estimators face daily. Since the introduction of BIM technology, some of these challenges have been significantly alleviated through improved workflows. In this article, the author shares insights on importing BIM data for estimation purposes.
1. BIM is only the starting point for estimation. Currently, no BIM software tool can fully and automatically convert a BIM model into a complete cost estimate. Although BIM models provide vast amounts of project information, this data represents only a fraction of what is needed for large-scale projects.
2. Getting started is easy. If you rely on traditional manual quantity takeoffs, your first step is digitizing these measurements or screening them for calculation using appropriate methods. Once estimators gain confidence working with digital quantity takeoffs, they can begin integrating BIM into their processes.
3. Begin with counting specific components. A practical way to leverage BIM for quantity estimation is by focusing on discrete tasks like counting doors, windows, or drainage pipes. Many BIM tools offer spreadsheet capabilities, along with simple query and calculation functions for specific elements or modules, which have been tested and validated.
4. Start with one software, then expand. It’s advisable to begin with a single BIM software or specialized cost estimation tool to reduce errors during data conversion. After verifying the accuracy of estimates produced by one program, model data can then be exported to secondary software for cross-validation.
5. Establish a clear and detailed hierarchy of estimated values. The level of detail in BIM calculations depends on the refinement of the overall building model. For example, if steel reinforcement bars are not included in the BIM model, their quantities won’t be automatically calculated. Estimators must understand the scope and meaning of the data contained in the model.
6. Focus on individual trades or component types first. Addressing challenges by concentrating on a single discipline or component category can improve accuracy and help resolve issues step-by-step.
7. Automation starts with standardization. To fully capitalize on BIM’s capabilities, designers and estimators need to collaborate on standardizing building components and their attributes related to quantity takeoffs. Additionally, standards must be developed for secondary components and accessories—such as wall bolts—to ensure their quantities are accurately derived. BIM objects may require updated definitions to include necessary installation dimensions, which may currently be missing.
In conclusion, these points highlight some key ideas on integrating BIM into estimation workflows. Of course, BIM’s role and applications in cost estimation extend far beyond these basics. As BIM technology continues to evolve and expand in domestic use, it will unlock even greater potential for improving estimation accuracy and efficiency.
Must log in before commenting!
Sign Up