Scan to BIM has become an integral part of capturing existing conditions for BIM projects. Creating a precise model allows confidence in your design and the ability to fabricate modules offsite and know they will fit when installed. We will discuss the different steps in the reality capture and model creation process in today's article. This model is an accurate representation of the existing conditions; you will sometimes hear the model referred to as a digital twin because of this. We will also examine some of the many uses of the reality capture process and how TPM may assist you in this process.
What Is Scan to BIM?
Scan to BIM is the process of capturing existing conditions, typically with a 3D laser scanner, to create an accurate as-built model of those existing conditions. In a traditional approach, people take field measurements and combine those measurements with current documentation to create an as-built model. This manual process can lead to outdated and inaccurate modeling, which has consequences throughout the project's lifecycle, such as project delays and costly rework. Using a 3D laser scanner, we can capture a highly accurate point cloud of existing conditions. You can then use this point cloud to create a precise model.
The Laser Scanning Process
3D laser scanning is a line-of-sight process. The scanner sends out laser beams that bounce back to the instrument and take measurements of the distances to all the surfaces it bounces off. Each of these points is captured and colorized based on the 3D photography taken in the scanning process. These individual points, collectively, are referred to as a point cloud. Because it is a line-of-sight process, scans must be taken from multiple positions to capture the existing conditions completely. The most important part of a successful 3D laser scanning project is for the person scanning to understand how they will use the point cloud and what they are trying to achieve with this process. Understanding the desired outcomes will allow the field crew to decide how dense of a point cloud to capture. This knowledge also helps the field crew identify the positions and number of scans needed to capture the detail necessary to create the desired model. Once the field crew captures all of their scans, they will come back to the office and register the scans together to create a unified point cloud of the entire project.
Using Point Clouds in the BIM Process
Most companies want at least one deliverable to be a point cloud in the Autodesk Recap format. This deliverable allows individuals to insert the point cloud into Revit, any AutoCAD-based products, and Navisworks. For some firms, the point cloud itself is the final deliverable they desire. These firms will model from this point cloud to create existing conditions. With today's tight schedules and high personnel utilization, many firms prefer to outsource their 3D modeling needs. Outsourcing both the 3D scanning and modeling to companies such as TPM allows firms to receive a fully developed model from the point cloud captured. This outsourcing saves internal bandwidth allowing your internal personnel to deliver more work and win more business. TPM can provide this model in a Revit or an AutoCAD format.
Some of the Many Uses of Scan to BIM
- Renovation: Creating an accurate and complete as-built model to avoid errors that may not be visible until the construction phase. Trying to solve these errors in the construction phase can be expensive and time-consuming.
- Construction: You can use scanning to create a record of the building as you are building it. Project managers can record this progress on a day-to-day basis. You can also use scanning to capture systems in trenches or walls before they are covered up. Scanning also allows you to compare the design model to the field's actual construction to find any discrepancies.
- Facilities: Most people don't have accurate and up-to-date models of their facility. Having this information allows you to make better planning decisions. You can embed data in these models to augment other facilities' processes.