Using drone technology to create a 3D model

Leading a Design and Build project from RIBA Stage 0 to 2, Walter Lilly engaged early with drone survey specialist ProDroneWorx to produce 2D/3D digital data using drone technology, creating a 3D Revit model for development planning and to include within the project BIM model.

Using the latest development in RTK/PPK drone technology, survey grade accurate 2D and 3D digital data outputs with global accuracies of approximately 40mm at a Ground Control Point (GCP) level were produced. The data enabled Walter Lilly to digitally understand this large project while providing deeper data insights, better collaboration on the project, and improving data deliverables to our Client while reducing costs and risks. In addition, the survey output was shared with the Client offering a digital massing and photographic ‘fly-through’ of their existing site.
The topographical survey of the site produced the following digital data georeferenced to the OSGB 1936 (OSTN15):

• 2D Orthomosaic
• 3D Mesh
• 3D Point Cloud
• 2.5D DEM
• 2D Contours
• Google KMZ
• Accuracy report

A 3D topographical and external Revit model was produced as a basic mass element white model from the drone survey data. This will allow Walter Lilly’s design team to accurately position the proposed building and progress the design with precise consideration to the surrounding site.

The survey was carried out in one day; this included the installation of the temporary ground control station and capturing the digital data. The HD images were processed using photogrammetry to produce the digital outputs that were ready within 3 days. This data was then passed on to the Revit technician for modelling which took a further 10 days. What used to take weeks, can now be done in days.

A digital twin of the project was created. The benefits of utilising survey technology for our project includes:

• A collaborative tool between the client, surveyors, engineers, designers, project managers and senior management to help understand the project related to the design models.
• Manage earthworks with cut and fill volumetric measurements.
• Enable progress monitoring of the project at all stages of the build against the design models.
• Quality assurance checks of construction materials used on site.
• The high resolution imagery can be integrated and used in BIM.
• Evidence regarding the amount of work carried out.
• The digital outputs can be used in virtual reality (VR) or combined with BIM.

The 2D/3D digital outputs can be integrated into existing workflow processes as the data was produced in various CAD, BIM and GIS formats e.g. dxf, xyz, las, laz, obj, e57, geotiff etc.