The goal of BIM is to produce a highly accurate and information rich model, which is to be handed over to the end user. Having an accurate BIM is especially crucial during preconstruction to prevent delays, waste, and produce accurate quantity takeoffs. One method of working efficiently during the 3D coordination phase is to use 3D laser scanning as opposed to using as-built plans. For renovations and tenant improvement projects this can be extremely beneficial.
There are many cases when the as-built plans are not up to date with upgrades performed on the building. Some most recent as-built plans are sometimes 50 years old. 3D laser scanning can alleviate this frustration by providing the most current and accurate information. The only challenges with laser scanning is that the 3D laser scanner works based on line-of-site, and modeling from the scan data can take some time depending on the level of detail desired. It is important that the scanning technician understand optimal placements for the scanner and to prioritize what needs to be modeled.
An example of the benefits of using 3D laser scanning in BIM is shown below.
The fire protection contractor modeled existing sprinkler lines from as-built line to tie in the new design as seen in the second image labeled as 2. However, when the plenum space was scanned, the data captured displayed that the as-built existing sprinkler line was off by a foot (indicated as 1). This can impact a project tremendously when every inch needed is required such as in hospitals.
If BIM aims to produce an accurate model, then 3D laser scanning might just be the right tool to be used for tenant improvements and renovations.