How Dura Vermeer used drones and AI in a major renovation tender

Housing corporation Vestia (now Hef Wonen) is starting a major renovation project in the Afrikaanderbuurt in Rotterdam. It involves a renovation of the residential block located on Pretorialaan, Paul Krugerstraat, Transvaalstraat and Putselaan (shaded green on the image).

Vestia's Development Project Manager at the time, Bas van Schelt, saw great potential in using a digital photorealistic 3D modelof the entire complex for the request for tenders and was also curious about the added value of the execution work for the contractor of this renovation project.

For Vestia, the traditional (manual) approach and execution of inspections, maintenance and renovation of their real estate portfolio (too) often resulted in subjective and inaccurate data that turned out not to be complete and accurate enough. This subsequently led, more than once, to unexpected costs and unverifiable additional work. Bas van Schelt wanted to get a better grip on this.

The key questions this posed to supRmen were as follows. Can supRmen create a photorealistic 3D model that Vestia and the contractors:

• provide a complete overview of the project site,
• which contains photographs of extremely high detail and
• can contractors also annotate in this 3D model the dimensions of window frames, doors and other building elements, and measure these elements and detect discrepancies?
• And can this also be done in the winter?

The team at supRmen knows the challenge involved in a project like this. SupRmen project leader Jasper Nederlof supervised this project: "Due to all the buildings and gardens being adjacent to each other, the project is more difficult to carry. In addition, there are some large trees in this one, which make flying the drones very difficult."

In addition, all homes are still occupied. In order to create as little inconvenience as possible, all residents, and surrounding residents, are being informed in detail. In this case, this was done by means of a letter. This letter contains the date when the work will be carried out. People and license plates are automatically blurred by an AI algorithm, so there is no invasion of privacy.

The data collectionis done from the air with a drone and from street level with an extremely high resolution camera. Combining these images creates a 3D model which also captures the undersides of a gutter or overhanging roof in razor-sharp detail. According to Jasper, this is impossible to do with public data, or satellites. "Of course this is accessible data, but it lacks the detail that technical people are looking for. People want to be sure it's correct, because otherwise you have to go back to the location anyway. The big advantage is that now you don't have to rent an aerial platform or scaffolding first." Collecting all the data took a total of 1.5 day. And that in winter. In summer, we would be even more efficient because the days have usable light much longer. In this model, a level of detail of up to a 2 millimeters deviation was achieved. In this way, the condition of a building becomes clearly visible and measurements can be made more accurately.

Once the raw data acquisition is done, the visualization phase begins . In this next step, images are blurred or removed that contain sensitive information. Then these images are computed together in special software. According to Jasper, this is "kind of knitting work for nerds." , but therein lies the secret of the smith. It is insanely important that this processing follows a tight protocol. This ensures that the models do not warp, or sphere. You want the 3D models to be reliable and you want to be sure that a centimeter is exactly a centimeter. And not 1.2 centimeters. From this then comes a complete photorealistic 3D model, visible through the online supRmen visualization platform Omnibase. Since the platform is online, the 3D models can be easily shared with all stakeholders involved in a project. All agreements, execution work, documents and other information can be linked to the supR platform. This makes all information centrally visible in one place. This way, we always keep everyone up-to-date on the progress of a project.

All contractors used this photorealistic 3D model to create their bids. After only two weeks, the contractors had their offers ready.

The contractors' bids were more accurate and more competitively priced. This positive effect was achieved because virtually everything was visible, allowing the builders to remove most of the risky assumptions that would lead to additional work from their bids.  

The 3D model served as a "infographic" between the Vestia housing corporation and in consultations with the contractor.

But perhaps more importantly, according to Jasper, "this made it much easier for the housing corporation to compare bids. Because the construction companies all worked with the same data, this also made Vestia's assessment qualitatively better." In this way it became possible for Vestia to compare the tenders like apples to apples.

Ultimately, the project was awarded to Dura Vermeer. To inspire other companies and housing associations, Dura Vermeer shared some factors with supRmen which had a positive result on their tender workflow:

1. The tender was presented in just 2 weeks, where usually 6 weeks is the norm
2. The model, which recorded the objective condition of the complex before renovation, could be used 24/7 as a reference tool. As a result, there was no need to go back to the site to take additional photos, avoiding discussions about additional work.
3. Fewer trips were made to the site each day to "to quickly do some additional measurements". This saved at least 200 work hours.
4. The number of home visits were also drastically reduced as a result, and thus the nuisance to residents.
5. The 3D model led to more efficiency and convenience. It allowed the team to better focus on the tasks that really mattered.

By using supRmen's photorealistic 3D models and building analysis, a building can be visualized "picture perfect". In this way, this technology helps unburden companies in the field of building inspection and building recording. The method is applicable in building renovation projects, but can also be used for planned maintenance, to make MJOB, and building condition measurements.

For future renovation projects, it is also interesting to use this technology in the field of quality assurance. At desired milestones, a scan can be made of a building's exterior and interior shell. This makes it possible to very precisely check which work was done when. Making it easier to compare different moments in time.
Read more about quality assurance or trend monitoring here