The benefits of scan to bim
Laser scanning is faster than manual bim modelling
A laser scanning process is the fastest method of 3D data acquisition for an existing building. Scan-to-BIM applied effectively considerably saves the time in the design phase compared to conventional on-site measurements. This method also minimizes efforts and time spent and cost of post-work when finding and fixing errors after the automatic BIM model generation process.
laser scanning is less error prone than traditional bim modelling
The surface accuracy of point clouds is high, making this a superior method for reproducing existing conditions in comparison to manual measurements. The accuracy of the points in the point cloud and average spacing between points in the processed point cloud is within 3 mm range. The accuracy of the surface model automatically generated from the point cloud with standard algorithms is within 5-10 mm.
Easily generate 2D cross-sections from BIM
Traditional 2D deliverables (plans, sections, elevations, details, etc.) can be generated directly from the point cloud data by taking virtual sections through the point cloud and generating drawings in conventional .dwg or .dxf format. When the end deliverable of the visualization of the scanned environment is animated in fly-through mode, HD quality movie files are easily available along with planned design features added. Using HD point clouds, the detailed 2D elevation drawings may be extracted that are delivered in *.dwg or *.dxf format or alternatively scaled orthophotograph elevations of the cleaned scan data.
From the 3D laser scan data fully rendered visualizations can be pictured from any viewpoint to provide detailed graphics of existing structures or environments and optionally incorporated design elements. The results of thermographic measurement may be superimposed on the visualizations of the scanned building.
the cons of scan to bim
Not always practical
In practice, as-built BIM modelling very often is done interactively in a time consuming and error-prone process e.g. with the BIM compatible software from major vendors like Autodesk Revit, Bentley AECOsim, Graphisoft ArchiCAD or Trimble Tekla Structures. Although some allow the rapid generation of building floor plans or offer BIM integration, the depicted software solutions are far away from automated or semi-automated BIM modelling of existing buildings.