Accuracy & Detail in Capturing & Modeling Data

Accuracy & Detail in Capturing & Modeling Data

Posted by Tim Crammond on 12th May 2015

While it’s tempting to go gallivanting off into the sunset with a brand new laser scanner in your arms, the practicalities of developing a scanning and BIM program that’s both internally effective and universally understood can pose a serious headache. Fortunately, two fantastic groups of individuals, the USIBD and BIMForum, have published specs for guiding both 3D documentation and BIM modeling. And while they won’t solve all your problems, the LOA and LOD will at least make that headache a little less annoying.

Level of Detail (LOD)

The BIMForum established the Level of Detail (LOD) Specification for AEC professionals in order to set a reference for communicating the elements and accuracy expected in a BIM or VDC document. The LOD gives form to the sometimes ambiguous process of BIM modeling, providing designers, owners, and project managers an appropriate criteria to inform both modeling teams and each other what information is required at each stage of a project. The spec also provides a baseline for estimating and bidding jobs, as well as managing project reworks.

Level of Accuracy (LOA)

Late last year the US Institute for Building Documentation (USIBD) released a set of documents that establish a criteria termed “Level of Accuracy” (LOA). These standards create a framework for establishing laser scanning project elements and nomenclature, equipping both service providers and clients with a vocabulary for communicating the work needed to successful complete a project. The Documents include suggested templates for RFP’s, RFQ’s, 3D Imaging Project outlines, as well as a LOA Spec sheet. All four provided templates come with sample sheets and detailed guides. The Spec sheet also differentiates between the different types of elements to be captured and assigns them a “normalized” range of accuracy.

The beauty of these two systems of qualification working in tandem is that it provides, at any stage in a Scan-to-BIM project, a specific standard to check work against. We’ve been encouraging our clients to implement both systems in all their projects if possible. Or, if you contract out either BIM work or Laser Scanning (ask us about our services!), we highly recommend you write in using the LOA or LOD as a requirement in the bidding and execution of the project.

Any questions about BIM, 3D Documentation, LOA or LOD? Give us a call or email us!