The technology of 3D scanning and converting it into a 3D model has its applications into various fields. In relation with the Building Industry (AEC), scan to BIM is the process by which a Building Information 3D Model (BIM model) is created from scanned point cloud data to accurately represent the ‘As Built’ environment. Bhushan Avsatthi, Associate Director, Hi-tech Outsourcing services explains further.
Scan to BIM is helpful and used in sectors like building industry, process industry and digital factory for the purpose of reverse engineering, ship building, documentation of accident and forensic scenes and facility management and others. The laser scan point cloud survey data is collected and registered by certified surveyors and it is this registered point cloud from which the BIM model is produced.
What is a point cloud model?
A point cloud model is a set of millions of data points within a coordinate system. These points represent the outer surface and the shape of an object. However, a point cloud model cannot be used as a BIM model. This point cloud data is used as a reference, and BIM experts trace upon this data to reconstruct a 3D model that is ready for BIM.
Scan-to-BIM process consists of three major steps: scanning, registration, and modeling. There are many inaccuracies and inefficiencies associated with each of the aforementioned processes that leads to inaccurate end product, as-built BIM, and also that increase the cost of Scan-to-BIM operations.
Benefits of Scan to BIM
The major advantage of the technology is in the ‘As Built’ sector. Especially on the much older buildings, there are almost no details available in terms of drawings or details. Laser scanning technology for a building is much quicker, more accurate and more detailed than compared to the traditional surveying methods.
It helps in creating an ‘AS Built’ accurate BIM model from the point cloud data, which saves significant time and cost for the client on the design side of the project. This helps in giving the design team, a much accurate and detailed 3D BIM model. Additionally it is possible to create a full set of ‘As Built’ 2D plans, sections and elevations from the BIM model.
This BIM modelling service and deliverable helps in providing a streamlined workflow for the design, planning and construction stages of retrofit, refurbishment and renovation projects, and also provides architects, engineers, government agencies and facility managers with a 3D model which contains the intelligent part as well.
For Scan to BIM tasks, what counts is the practical experience. Based on the experience and learnings , the professional gets while working on the various projects, the below mentioned points are taken care of:
It is very much essential to get the précise and detailed brief of the project, as it can be challenging due to the nature of Scan to BIM project and especially for the project involving the interior modeling. There comes a situation, where client can request for a pricing without providing the scanned data. In such cases, one needs to make sure to receive the photographs and/or videos of what is going to be scanned and study them carefully. It is very likely that the service provider either provides under price and suffers heavy loss or over price and lose the contract. If possible, it would be advisable to make a site visit and study the building components such as beams and columns and their junctions. One needs to study the site condition as well, as it would also influence the modeling process.
In case where client provides with the scanned point cloud data, it would be much beneficial to get the 3600 colored panoramic views, which gives a clear idea to the modelers about the existing conditions. Many of the recent scanning machines have this facility.
Level of Detailing
This is a very important point to be received from the client or to be mentioned in the scope of work provided by the client. The Scan to BIM projects are quite different as compared to the visualization projects. The former one mainly requires to focus on detailing part, whereas the later one is mainly for a presentation in a 3D format. The level of detailing applies to architectural, structural and MEP part of the project.
For the regular BIM projects, it mainly deals with the LOD 100, 200, 300, 400 and 500, which are mainly related to the design part. For the Scan to BIM projects, there are levels 1-5 which are referred to while discussing the details to be considered while modeling. Here, one needs to make sure that one’s understanding is on same lines with that of the client.
As evident, the Scan to BIM is comparatively very new technology and process. There are cases, where the client is not fully aware about what he is asking for in reality, while the project is being discussed. It would be required to educate clients thoroughly about the process and about the output that would be delivered. This would help avoid any disputes during the project process or at the time of final deliverables. The practical scenario differs from the theoretical part.
The scan to BIM conversion is a very specialized service which involves complexity and exactness, of the modeling especially for the ‘As Built World’. The precision is of utmost importance linked to the modeling part.
The future of scanning is immense and the different ways we scan will continue to evolve and become more customized to the specific industry problems presented. Point cloud data is still the best data that exists for capturing and studying existing conditions. The future will be exciting to watch for sure.