Nouveau architectural visualization: VR walkthroughs with Groupe Legendre

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Groupe Legendre is a major construction, real estate, and energy group with offices and projects across France, the UK, and Algeria. The company has been a pioneer in the field of virtual reality for architectural visualization, showing their clients immersive representations early in the process to invite feedback and collaboration. 

“The majority of our clients aren’t building engineering experts, and most have never tried VR before,” says Antoine Guillo, Virtual Reality Designer at Groupe Legendre. “Being able to discover their own projects in room-scale virtual reality is a unique experience for them, and so much more effective than 2D plans and drawings.”


Guillo and his preconstruction team of around 15 designers and engineers have been creating VR, AR, and flat-screen visualizations for clients for several years. With the most recent updates to Datasmith, they can get clients immersed in these 3D experiences at an unprecedented speed, sometimes just a couple of days after starting the project.


Building a VR pipeline


When they first started exploring real-time rendering for VR, Guilllo’s team experimented with a variety of solutions. They chose Unreal Engine for its image quality, Blueprint visual scripting, and ease of use.

Before Datasmith became available, Guillo and his team initially developed a pipeline where they exported Revit models to 3ds Max, then imported those scenes to UE4 using FBX and MAXScript. While the image quality and client navigation tools in Unreal Engine worked out great on the client-facing end, the development process had its limitations—data-prep and cleanup were time-consuming, and the team had to gather BIM data in a spreadsheet and export it separately.


When Datasmith was released as part of the Unreal Studio beta, Guillo and his team started using it instead of FBX to import the 3ds Max files. “From the beginning of the testing phases, we were hooked by the simplicity and effectiveness of Datasmith,” says Guillo. 

But while Datasmith improved processing times, Guillo and his team wanted to take things a step further and go directly from Revit to Unreal, thus avoiding the conversion to 3ds Max in the middle. “We suggested to the Datasmith team that a Revit plugin might be a good idea, since a good number of BIM engineers and architects use it,” says Guillo.

When Datasmith for Revit was released earlier this year, it was love at first use for Guillo’s team. “It removed a massive weight off our shoulders,” he says, adding that the tool sped up import by up to 100x. 


“Our processing times improved so much, we could prepare a client demo in less than a week, when previously it took more than a month to build,” says Guillo. “Recently, we were able to produce a video, render the stills, and build a VR demo in less than two days!”


Hooking clients with VR


With their speedy new Datasmith pipeline, Guillo’s team is taking on ever more ambitious projects and continuing to wow their clients with VR. “All our clients are impressed by our demos,” says Guillo. “We so often see what we call the ‘Oh face’, where they put on the headset and just say, ‘Oh! Oh!’ over and over,” he laughs.


Guillo adds that the use of VR isn’t just about impressing clients—equally important is the feedback for the design and engineering teams. “We gather all the clients’ comments at the earliest steps of the project, and our specialists are able to then modify the building models accordingly,” he says.

Groupe Legendre’s most recent projects include a fully customizable and interactive virtual apartment for a high-end building, and a demonstration of a future office building to over 100 of a client’s employees. They’ve also been to events all over the world to showcase what VR can do for architectural visualization and BIM engineering.


The future of VR for archvis


Guillo sees an even brighter future for VR going forward. In their continuing quest for high-fidelity VR, his team has been experimenting with real-time hybrid DXR ray tracing, a new feature in Unreal Engine 4.22, on their new NVIDIA Titan RTX GPU. “We tested some of the new ray tracing features, and it’s pretty exciting,” says Guillo. “We’ll save time by not having to bake lightmaps, and we’ll be able to upgrade the fidelity of our renders through realistic material reflections and global illumination.”

In the meantime, Groupe Legendre uses Unreal Studio for 80-90% of its projects, with plans to bring that number to 100% in the near future. “The biggest challenges we face with CAD AEC data are scene optimization, precision, rendering quality, keeping BIM information, and developing an interface that our non-technical clients can use,” says Guillo. “Unreal Studio delivers all of that, and more.”

To start creating your own VR experiences for architectural visualization, download the free Unreal Studio beta, then check out our free video training series on architectural interiors with Datasmith.