The utilisation of aerial photography and laser scanning in BIM modelling

The use of BIM model in the designing process of new buildings has been growing significantly. The reasons for this growth can be found in the increased productivity and improved information sharing. The model can be used to create all plans, sections and elevations necessary on the construction site without the need of drawing them all independently. To use the benefits of BIM modelling in projects containing existing buildings, the existing building has to be modelled. This is done by using scan-to-BIM, which uses point clouds. These point clouds can be created using 3D-laser scanning and/or aerial photography. Laser scanning is the best way to document the indoor environment of a building. Documenting the outdoor environment of a building using laser scanning can pose its challenges, especially for the roof. Using aerial photography is a solution, this uses close range-photogrammetry where photos can be used to construct a 3D model when objects are visible in multiple photos. Combining both point clouds to a single point cloud is possible by georeferencing both clouds, using the coordinates of the targets from the scanning and the ground control points of the aerial photography. Working in a point cloud has limited possibilities so converting the point cloud to a BIM model opens up these possibilities. The geometry inside the model is clearer and information can be added. This is done by using BIM software such as Autodesk Revit and modelling walls, doors and windows where the scans show them. This manual process is time-consuming and can be facilitated by using a special point cloud to BIM conversion software, which helps with the placement of walls and detects wall thickness. In order to test this kind of software, a model was made of an old train station in Tampere which will be moved in the summer of 2020. The building was scanned and aerial photographs were available. These scans and aerial photographs were used to make a single point cloud, which was then used to model the building in Revit using the Faro As-Built software as a tool

Soil phosphorus tests compared on established European long-term trials: which test is the winner?

status: publishe