To understand Scan To BIM, you first need to know what BIM is.
According to the National BIM Standard Project Committee in the United States, “BIM is a digital representation of the physical and functional characteristics of a facility. It is a shared knowledge resource of organizational information, forming a reliable basis for decisions to be made. BIM is in other words defined as existing from earliest conception to demolition. ” This definition and BIM practices are essential for understanding and carrying out the Scan To BIM approach.
Scan To BIM is an as-built survey process using lasergrammetry or photogrammetry that captures information about the environment scanned . The survey device digitizes 3D information and data in the form of millions of points which, when assembled, form point clouds. Point clouds are processed, used and analyzed to serve as a support for the BIM (Building Information Modeling) process which consists in creating a 3D digital model from the capture of reality and point clouds. In addition to modeling the existing physical space, 3D models can be added to anticipate and simulate changes to be made to the building as built.
The Scan To BIM workflow
The use of 3D laser scanners
3D scanners are advanced technologies that are designed to improve, facilitate and accelerate the survey phase in the field. This is how the term 3D survey appeared, with traditional information measurement methods being too imprecise and requiring significant labor both in the field and in front of the computer. The scanners project a laser in all directions around its axis, while rotating on itself so that they can pick up all the environmental information around it. It takes into account the entire more or less complex structure of its environment to be able to deliver them in the form of point clouds that can be used for 3D modeling and the BIM approach.
During the 3D survey, the scanners digitize the “as built” information which is then deliverable to digitization software such as ReCAP in order to assemble the scans and obtain a complete point cloud. This assembly phase is called registration (click here to read the article on assembling scans).
Point cloud to BIM
The point cloud is an information delivery system that maps physical space and represents the modelable digital twin of an object or environment that the 3D laser scanner has identified. It gives visibility to the current project even before providing details through 3D modeling. This saves time, efficiency and speed that facilitates the coordination and completion of the project, while reducing the margin of error that a surveyor or architect can perceive when taking his measurements on site. Point clouds are used as a solid foundation to create 3D BIM models and digital models. After their assembly, the point clouds can be processed, exploited and analyzed using software or platforms such as ATIS.cloud which will allow users to be able to visualize the information captured from the 3D survey, to process the 3D data and to share them using advanced tools in order to work on the point cloud. This step is essential to accelerate 3D modeling, the measurements, annotations and project information being referenced and centralized on a secure online platform.
Subsequently, the point clouds (or part of the point clouds that need to be modeled) are exported to design software (CAD software such as ArchiCAD, AutoCAD, Revit) in order to be able, with the help of information delivered by the point cloud, create a 3D model. BIM is today in most advanced countries a standardized planning method that complies with construction, design, renovation standards and which is in some cases imposed on AEC companies or strongly recommended. All the steps of the Scan To BIM promote collaboration between the stakeholders of a project and each one can modify, update and extract information from the BIM model.
Finally, a BIM model is an assembly of geometric objects from a database established as a 3D model is created. It is therefore necessary to be able to define the level of detail of the components of the structure in order to establish a common reference point between the actors of the construction. These levels of details (Level Of Details LOD) are included on a scale from 100 to 500 depending on the precision of the structure of a 3D model. LOD 100 is a level of detail that represents little if any of the object as built (a cube to represent a house or the slope of the roof may not be modeled. LOD 500 is conversely a level of detail precise or one will model the presence of all the bolts on a piping network or steel in reinforced concrete.
The challenges of Scan To BIM
Problems that Scan To BIM can solve
Collecting data from a structure or environment is very complicated and requires a lot of time, precision and organization. Getting to an environment is not always an easy task. In fact, access to the site is sometimes difficult and measuring the structure is a long process and the presence of natural or artificial obstacles can slow down the collection of information or even prevent it. All these conditions must be taken into account and are issues that affect time, budget and human or technological resources. Scan To BIM technology is a new working method which, through the 3D survey phase, allows to capture a maximum of extremely precise information, quickly and to deliver the data collection in the form of point clouds, viewable on a computer.
The documentation of the “as built” building is often outdated or fragmented or both. Moreover, it is regularly updated through the processing and use of data in point clouds or 3D models. The Scan To BIM approach facilitates the monitoring of modifications and simulations in order to create a coherent and relevant BIM model. These updates and modifications can be viewed and interpreted by all users of the BIM model who collaborate on a team project.
The benefits of the Scan To BIM approach
The most notable advantage is that errors in modeling and project planning are reduced. These potential errors are avoided by an optimal and precise collection of information and environmental data, but also by the superposition of the 3D model and the point cloud, in order to increase the quality level of the modeling.
Then, Scan To BIM provides a quality of work essential for the AEC, since each step of the modeling and each progress in the realization of a project is shared with the stakeholders. Site inspectors reduce their trips without losing visibility and understanding of the project. Access to construction or renovation sites is easier because the workforce employed is reduced and measurement is facilitated, especially if the environment reveals obstacles hindering the collection of information and complicating the visibility of the structure components.
Finally, property managers can anticipate the completion of development work more easily. 3D scanning and point cloud processing make it possible to visualize the entire structure of a building and the electrical and mechanical systems that make it up. It is then easier to plan insulation work to reduce their carbon footprint, to organize and simulate the layout of the furniture according to the electrical and mechanical systems.
Scan To BIM is becoming an easier-to-access standardization for AEC companies thanks to technological advancements in point clouds. The Scan To BIM approach is also a major factor in the progression of the BIM process, which increases its use in construction projects. Cost reduction, time savings, ease of access to site data and stakeholder collaboration are significant benefits provided by Scan To BIM, which has essential advantages for standing out in a competitive market.