Model-based stake-out from 2D plans: BIM2Field with QR codes
More and more construction projects are being planned with building information modelling (BIM). However, 2D plans are still used at many construction sites. This creates considerably more work and results in a greater risk of errors when staking out the construction site. Basler & Hofmann recognised this problem and teamed up with Leica Geosystems to develop an innovative workflow for model-based digital surveying from 2D plans. The key feature of the process: QR codes.
While the technology exists for staking out construction sites directly from a BIM model, it is not always possible. “Many clients worry that the digital models might no longer be available in the distant future due to software updates, which is why they decide to work with and archive 2D plans,” explains Mathias Kuhn, leading expert in Digital Planning at Basler & Hofmann. While that does sound logical, Mathias Kuhn is convinced that “if we want to get the most out of digital models, however, we will need a fully integrated process in the future. Together with Leica Geosystems, we therefore asked ourselves how we can reap the benefits of staking out projects directly from the model even when working with 2D plans – a sort of intermediate step as we move towards a purely model-based process.”
QR codes as a data medium for stake-out data
The collaboration produced an intuitive workflow that uses existing processes and technologies. “Our goal was to develop a process that is accessible to everyone working on the construction project, no matter where they are in terms of technology,” explains Mathias Kuhn. So the process is quite simple as well: the planning team prepares 2D plans from the model in the usual way. In the process, a QR code is generated for each point that is to be staked out. This code contains the coordinates. No dimension lines or lists of coordinates are needed. To generate the QR codes, Basler & Hofmann built an add-in for Revit’s Autodesk modelling software. The add-in is publicly available on GitHub. The surveyors at the construction site scan the codes with the Leica tablet’s built-in camera. The points appear automatically in the Leica iCON build software and can be sent from the tablet directly to the total station. Using a web-based application, the points can also be scanned directly with a smartphone to easily calculate the distance between two points, for example. “The app allows us to make sure that both the client as well as smaller developers without certain equipment can read the data and take advantage of the benefits of an integrated data flow,” explains Mathias Kuhn.
Higher efficiency, fewer errors
The new workflow makes the benefits of a fully integrated data flow come alive. Firstly, the process offers higher efficiency: when preparing plans, there is no more time-consuming drawing of dimension lines and preparing separate lists of coordinates. The construction stake-out team can skip the tedious preparation of data before heading out to the site. Secondly, the workflow minimises the risk of errors: because a list of coordinates is no longer needed, there can be no discrepancies between the plan and coordinate list. The surveyor team can be confident that it is always working with the latest version of the data since all of the data is taken directly from the model. Mathias Kuhn believes these improvements will ultimately benefit the client.
Mathias Kuhn, leading expert in Digital Planning at Basler & Hofmann: Contact
QR code add-in for Autodesk Revit
Publicly available on GitHub