Today’s Construction Takeoff consists of a mix of realities and negotiations.
The process of listing and measuring the work done in a construction project is usually a combination of measurements taken from lay-outs and on-site measurements an inspection. This complex task is often delegated to site managers who may lack the expertise or time. Errors highly impact on the final cost estimate. Dependence on the skills of the person in charge and using a manual workflow turns out to deliver are an error prone result.
Digital scanning and 3D modeling can significantly improve the efficiency of construction takeoffs and final estimates
DIGITAL WORKFLOW
- Reality capture: Currently, there are affordable devices that allow the capture of the geometry and details of a worksite. We are thinking of drones, photogrammetric cameras and laser scanners. Each of them has its applicability and restrictions, and the scanning frequency must be determined for each project according to the construction type and specific needs.
- Data processing: The final goal is the generation of a point cloud or sometimes a virtual tour as well. For the first, the stages are interpretation, filtering, calibration, registration, and generation of the point cloud. Fortunately, these are automated in most existing software.
- Scan to BIM: The point cloud is compared with the pre-existing 3D project model. The most common practice is to compare the point cloud with the pre-existing 3D model to identify discrepancies and create an ‘As-built’ model. This task still requires human intervention, although there are certain helper applications that tend towards automation. The use of high-quality photographic virtual tours allows high level guidance for the model update.
- Output: Using interoperable software, the model can generate automatic takeoffs, cost estimates, progress reports, issue tracking reports, and an ‘As-built’ model.
BENEFITS
Greater transparency: a documentary record of the construction process is kept during the work, being available for consultation or review by any stakeholder.
Greater accuracy: there is no manual work involved on the critical steps avoiding not easily tracked errors.
Less disputes due to different interpretations between stakeholders.
Independence from the skills of the estimator or person in charge.
Beyond the aspects of measurement and certification, we also obtain:
- Generation of an “As built” model of the work.
- Base model for a later digital twin.
- Change and failure tracking along construction.
- Construction schedule control.
Digital workflows are the path for an efficient construction management.