Virtual To Actual, Black Art Of Laser scanning for BIM – Over Hyped or Aptly Described?
When laser survey and point cloud modeling first arrived there was a sense of awe and wonder. As built structures were scanned and converted into 3D models so easily. Today as scanners and related software have become more advanced, and the BIM authoring tools have also evolved – 3D Laser scanning to accurate Revit and BIM is transforming the way building owners and designers gather the construction details and information about existing buildings and structures.
Eventually, Scan to BIM, has become the most popular and the talked about technology across the AEC industry. However, some skepticism and doubt still prevails across some sections of the industry. This skepticism is primarily because, point cloud surveys collect only what is visible, more over there can be inconsistencies in the
So the Question Here is to Scan or Not to Scan?:
There are several existing buildings that are old and need renovation however, due to lack of availability of proper documentation renovation becomes difficult. This is where laser scanning and point cloud modeling comes in. Suppose you collect the structural data for a building, consisting of shapes, mass and color, it becomes easy to plan MEP network within this structure such that there are no clashes between the structural and MEP disciplines. This is where it is also possible to use Point cloud for clash detection and mitigation. However it is absolutely essential to consider some aspects of laser scanning before you decide to adopt the technology for virtual recreation of a As built facility.
Are these point cloud models ready to use? The survey data is made of thousands and millions of points and it needs to be traced upon and resurfaced to convert it into a model with polygons. Now it becomes ready for BIM.
It is absolutely true that point cloud survey can be costly. It requires a lot of on field work and the laser scanners that are used for laser survey are also costly. Another point that requires a mention here is that, the surveyed data (a considerably large building requires minimum 250 to 300 scans) can be large, and it requires lot of RAM and storage space to store and process the point clouds and convert them into intelligent information rich BIM. As a result we can say that it is not for small scale projects, however for huge commercial, infrastructural and palatial properties in addition to heritage buildings and properties of architectural significance scan to BIM can be a valued proposition.
There is absolutely no doubt that using laser surveys, it becomes extremely easy and a fast tracked process to collect raw data. But there are some aspects to be mindful of. It is true that point cloud surveys cannot collect data in entirety. Apart from the fact that 3D scanners cannot capture details of hidden objects, it is also true that the accuracy and amount of detail collected does not solely depend on the type of scanner. The expertise of the survey professional also plays a major role.
Based on the cost benefit analysis it should be decided whether to scan or not to scan for a particular renovation, reconstruction, or refurbishment project.
The Point Cloud to BIM – Phenomenon And Evolution:
Laser scanners are getting smarter, compact and more accurate. The cost of scanning is hence coming down. If laser scanners become affordable even for developers who are working on very small scale projects, it will bring another revolution in the building and construction industry. The use of laser survey will become common place, and even a small two storey building construction project will be able to leverage the benefits ofpoint cloud to BIM for through documentation, clash detection, fast tracking the construction process and much more. The future of laser scanning and conversion to BIM will not be limited to documentation and renovation/retrofits/repair projects but will also be used during the construction projects to scan installed structures and check them against design models. Reference e-architect