Why the need for a Survey Specification?
Plowman Craven has been involved in number of projects requiring both 3D laser scan data and BIM-ready models to be delivered as part of the platform for the BIM process going forward.
The most efficient and successful of these projects have been those where clear communication and collaboration existed from the very beginning. Although objectives and expectations are always discussed and a full understanding of the requirements documented, the lack of a survey specification or reference document often prolonged and complicated this process. A majority of projects and requests followed a similar pattern and it was determined there was a need for a set of BIM Survey Specification rules. The absence of a set of guidelines meant there were continual variations to the requirements and expectations.
The Plowman Craven BIM Survey Specification is a comprehensive set of guidelines aimed at providing:
- A greater understanding and communicating of all model expectations
- Reduced variations and changes to requirements
- Smooth delivery within pre-established timeframes
- Effective cost control for all parties
We understood that to create a document to cover all scenario’s, applications and software’s would be a considerable task, so our initial focus was to cover options for creating models of existing buildings or structures using the Autodesk Revit® application.
What’s in the Plowman Craven BIM Specification?
- Technology and Workflow – An outline of the differing technologies applied to gather 3D data. Suggested workflow and stages to achieve the desired outcome
- Level of Survey Detail – 5 levels of content outlined and illustrated
- Accuracy and Modelling Tolerances – Survey considerations: control, scan registration, scanner types, survey method – Model considerations: building nature, verticality, purpose, usability
- Project Considerations – Point cloud density, inaccessible areas, quality checks, deliverables, liability
- Detail Check List
- Detailed Modelling Considerations – An overview of specific considerations such as – worksets, phasing, constraints, warnings
Peter Folwell, Director, Plowman Craven Limited