BIM and reverse design with Jérôme Loywick from Bouygues Bâtiment Nord-Est
Hello Jérôme, you are a BIM Manager and BIM specialist at Bouygues Bâtiment Nord Est, what is your background and how did you get into BIM?
My background is a little atypical, because I started studying in the field of mechanical, before reorienting myself after my license in the field of construction. When entering the professional world at Bouygues in 2009, I was surprised to see the low level of use of digital tools in the building industry, while in industries, these tools have a very important place for the design.
The first project I was involved in at Bouygues was the construction of the new Calais hospital center, and the works team was motivated to produce a digital model of the project. Very quickly, applications were found: operating modes, cycle plans, extraction of nomenclatures, ...
Since then we have been using the digital model on almost all of our projects with specific applications for design, construction or operation.
What types of buildings are you working on? What are your missions ?
I had the opportunity to work on the implementation of BIM and the digital model on operations of heavy rehabilitation, habitatbuildings industrial or even works functional. Perhaps the most memorable project is the Lille administrative court, for which we won a Silver bim in the renovation category.
My main missions are the implementation of protocols and processes to work in collaborative BIM on projects with architects, design offices, or partner companies. During the realization phase, I intervene for the architectural and technical synthesis. I am also a referent for the implementation of digital tools on construction sites, and support for our customers for the use of BIM during the operational phase.
Could you tell us about retro design in the building? In which cases is this technique used?
In mechanics, reverse engineering consists of generate solid geometry from a real object. This technique is used to improve mechanical parts, by doing rapid prototyping, or to recreate molds.
For the building we use a 3D scanner to accurately capture the geometry and position of elements. I used this technique in particular for rehabilitation / renovation projects for which we did not have graphical input data (cried, DOE, ...)
Could you give us a few projects where you used reverse engineering?
The most recent being a project to extend and modernize a 42000 m2 logistics center, on behalf of a large German distributor. We did not have a plan of the current state of the building.
For the Administrative Court of Lille, we also proceeded in the same way.
How do you actually proceed during a reverse engineering mission?
Le A cloud of dots which was obtained following the scan of the building is integrated and georeferenced in Revit. This serves as "skeleton"to the 3D modeling of the building, which makes it possible to guarantee a model"the built"with an accuracy of less than 5mm. The next step is to model the elements from sections in the cloud of points.
There are also methodologies to model the structure in a way semi-automatic thanks to a algorithm.
Do you have any advice or specific feedback on how to make a reverse design more successful?
To guarantee a faithful modeling, care must be taken not to havedisturbing elements during the realization of the 3D scanner. For example, it is better to have the structure visible (without the dubbing or faux ceilings).
During a modeling manuelle, it is sometimes difficult to faithfully transcribe the imperfections of the building (distorted floors, curved walls, etc.). We must therefore think ofend use of the BIM model and adapt the level of precision accordingly. For example, if we plan to set up structures from the 3D model, it will be necessary to give great precision to the location of the existing structures!