The definitive guide to scan-to-BIM
The term scan-to-BIM refers to a workflow that uses 3D scanning to document an existing asset and turn it into a BIM model. It was developed as a way to bring existing buildings in line with the latest documentation and planning methodologies.
For more detail, let’s break it down term by term:
- Scan: 3D scanning technologies, e.g. mobile or terrestrial lidar. These tools are used because they capture an accurate, comprehensive, and detailed point cloud data set for the real-world building.
- BIM: Building information modeling, a powerful AEC collaboration methodology. In a scan-to-BIM workflow, the final deliverable is a BIM-compliant 3D model.
Why should you care about scan-to-BIM?
Scan-to-BIM is an increasingly valuable (and lucrative) service for scanning providers to offer.
That’s because BIM is more than a passing trend for your AEC customers. Most companies and projects have accepted it as an extremely effective methodology for collaborating more effectively throughout the entire building lifecycle. Many government bodies have even begun to mandate BIM, so its use in AEC will only continue to increase as time goes on.
The catch is that an AEC company needs detailed 3D models of a building to do good BIM. For new projects, this is easy enough, since 3D data is generated by designers and planners during the early stage of the project.
However, for projects that aim to update existing buildings, getting 3D data for the asset isn’t quite so simple. That’s because a great majority of the buildings in the world were constructed before CAD modeling and other digital methods became popular. If the building comes with as-built documents or floor plans, they are often limited to 2D—or wrong. The most likely outcome is that the documentation just doesn’t exist.
This is where you come in. Projects regularly hire laser scanning professionals, or work with internal scanning specialists, to produce detailed 3D captures of their assets. This in turn, enables them to use BIM methodology throughout the rest of the building lifecycle, for better financial results.
If you’re going to take on scan-to-BIM projects, it’s important to know the basics of BIM. Here’s a quick primer.
What is BIM?
There is a standard, accepted definition of BIM. According to the National BIM Standard Project Committee in the USA:
“Building Information Modeling (BIM) is a digital representation of physical and functional characteristics of a facility. A BIM is a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle; defined as existing from earliest conception to demolition.”
What is a BIM model?
As we discussed earlier, a BIM model is a 3D model optimized for use in the building information modeling methodology.
It includes spatial data, such as geometric design models or real-world 3D data captured by lidar or photogrammetry. The BIM model takes this a step further by connecting this spatial information to a database containing important functional and attribute data about the building. That might include materials used, size of rooms and spaces, or a breakdown of the interrelated parts of the HVAC system.
In truth, a BIM model can include any data that is deemed important to project stakeholders. It can even include scheduling information, or data about sustainability.
What is the value of BIM to your AEC customers?
BIM methodology provides stakeholders with all the most current data on the project, including spatial information, functional information, and every recent change made by other stakeholders.
This, in turn, helps teams to plan, design, construct, and manage a building much more effectively by keeping project stakeholders up to date, and enabling them to coordinate their work on an asset.
In short, BIM enables projects to keep work running smoothly, eliminate surprises, and improve their financial results.
BIM applications throughout the project and building lifecycle
BIM’s effects are complex and its benefits extend throughout the whole life of the building.
Here are three examples of how BIM can be used throughout the building lifecycle.
- Design and Planning
Good BIM enables trades to work together in a common data environment and optimize building plans before construction begins.
For example, stakeholders can use it to perform a type of planning called BIM coordination, which orchestrates the work of MEP engineering, structural engineering, and architectural design teams during the design process. By combining the different design models into a “federated” BIM model, BIM coordination makes it easy to see clashes or scheduling problems as soon as they arise, like a run of pipe that exits through the floor rather than inside the wall.
A BIM model aids in the construction stage by making a wealth of information available (and easily understandable) to all stakeholders.
A properly generated BIM model will be accurate and include the most up-to-date design data from all trades, as well as important scheduling information. As a result, some projects will use it as a reference for prefabricating building elements. In this application, the BIM model enables them to build elements offsite at tight tolerances, and then move them to the asset for installation at precisely the right moment in the building sequence to prevent clashes.
- Operations and Maintenance
Some estimates put 70% of the building’s total costs during this phase. A good, up-to-date and precise BIM model can go a long way toward reducing these costs.
The BIM model will include detailed, up-to-date information about a variety of building elements and systems. That means a maintenance worker or owner-operator could use it as a reference for information about the location and age of specific machines, how many parts are in an HVAC system, which kind of lightbulb a lamp uses, when repairs were last performed on a door, and a lot more.
How to perform scan-to-BIM
Now that you understand what BIM is, and why it’s important to your AEC customers, let’s dig into how you can perform your own scan-to-BIM workflow.
Depending on what kinds of resources you read (and you’re probably going to read a lot about scan-to-BIM before you get out into the field) the workflow can be broken down in a number of ways. We will talk about four different stages: project planning, scanning, data processing, and modeling.
Stage 1: Project Planning
Like any project, a scan-to-BIM project will require careful planning. Make time before work begins to talk with your client about their BIM plans. Discuss questions like their intended applications for the BIM and their accuracy requirements. Compile all this information into a scope of work (SoW).
This will help prevent nasty surprises later in the project, and ensure that you and your client are on the same page.
- Talk to your client about their needs
- Get important project details
- Use standards documents for absolute clarity
- Define a scope of work (SoW)
Stage 2: Scan Planning and Field Execution
Once you’ve locked down the project parameters with your client, you’ll need to plan the actual scanning work. No matter your level of experience, this is a good opportunity to make a solid plan for how best to approach the scan in the field and produce the best results for your client.
If you’re new to scan-to-BIM, be sure to think about this stage before you take on your first client. It will help you think about what kinds of scanners you’ll need for different kinds of projects.
- Pick the right scanner
- Develop a hybrid workflow
- Use survey control
- Make a scan plan
- Take notes
Stage 3: Data Processing
After capturing the data, you’ll need to prepare it for the modeling process. To do this, you’ll finalize the data in your processing software, clean up unwanted or erroneous data, register your scans together, and perform various checks to ensure that you’ve met coverage and quality requirements as agreed on in the scope of work.
If this is your first time processing data for a scan-to-BIM workflow, you’ll also want to ensure that your computing hardware can handle the huge data sets you’ll be working with.
- Keep talking to your client
- Check your processing hardware
- Consider cloud processing
- Clean your data
- Register—and then QA again
Stage 4: Modeling
Once the data is prepared and you have double- and triple-checked it to be sure that it meets requirements, you’ll turn that 3D data into a geometric BIM model.
If this is your first scan-to-BIM workflow, you’ll need to select your modeling software from a range of options, determine your modeling personnel, and plan out your workflow to make the most of your employees’ time. At the end of this process, you’ll likely hand the work off to your client for their BIM work, so it’s your last chance to make sure everything is right.
- Pick the right modeling tools
- Think about your modeler
- Time management is key
- Send your client a test model
You might still have some questions about BIM, or scan-to-BIM workflows. Here are answers to some of the most common ones.
What is the difference between BIM and VDC?
Building information modeling (BIM) and virtual design and construction (VDC) are both methodologies used by AEC professionals. The difference is focus: VDC is a method for using digital models, like BIM models, to plan a construction project. The goal is to plan scheduling, finances, sequencing, and so on before any workers get into the field.
BIM is a methodology for managing collaboration in the actual building and management process. The two methodologies can overlap—and often do.
What is the difference between a BIM model and a 3D CAD model?
Both types of models contain geometric information about a real-world structure. However, 3D CAD uses “dumb” lines to represent a building, meaning the lines are not grouped together into objects within the model.
For example, you may look at a drawing of a window in a CAD model and know that you are looking at a window, but the CAD model thinks of that window as a set of unrelated lines.
BIM models, on the other hand, do group lines into objects. The BIM model will know that a window is a window. This is useful for linking geometric information to functional information about the asset.
What is the difference between a BIM model and a digital twin?
You can think of a BIM model as being a step on the way to a digital twin.
Like a BIM model, a digital twin is a representation of that building and the systems contained within the building. However, a digital twin adds real-time information from a variety of sources, such as internet of things (IoT) sensors that can measure the movement of a crowd, temperature throughout the different spaces, gas levels, and anything else that can be captured by sensors.
In other words, it’s exactly what it sounds like: A digital “twin” of the real-world building as it exists right now, in the real world.
This extra data enables digital twins to look into the future through simulation. Many owner-operators will process a digital twin’s real-time data with machine learning or other AI tech and use it to test out possible changes to the asset. That could tell you, for instance, what might happen to the pedestrian paths if an extra outdoor staircase were added. Or it could tell how much faster your assembly line might operate if you moved that shelf of parts closer to a specific worker.
What is 4D BIM? 5D BIM?
BIM “dimensions” refer to the types of information reflected in the model. Here is a quick overview:
- 3D BIM is the classic BIM model. It includes spatial (ie, three-dimensional) information and a database of functional information.
- 4D BIM adds scheduling information, corresponding to the dimension of time. This enables projects to sequence their construction to avoid clashes.
- 5D BIM adds cost information. This is a loose definition of a “dimension,” but it enables projects to do more precise financial planning by seeing what costs will be at different stages of the construction sequence.
- 6D, 7D, 8D… are non-standard BIM dimensions. Some projects or agencies will use them to refer to information like sustainability, but its best to stay away from these designations and discuss the necessary data directly with your client instead.
What are the BIM levels?
A BIM level refers to the maturity level of the BIM used by a specific project. It indicates the extent of collaboration between stakeholders, and the level of digitization of the project.
- Level 0 – Essentially the absence of BIM, this means little to no collaboration and zero digitization.
- Level 1 – Partial collaboration between different disciplines on the project. Projects use 2D and 3D CAD, and information is shared in a common data environment (CDE).
- Level 2 – Projects are fully Stakeholders across disciplines use intelligent BIM models and combine their data in a CDE. The project most likely uses 4D or 5D BIM.
- Level 3 – Improves on level 2 by bringing full integration. Intelligent data sets are combined in a single, federated model which operates as a single source of truth.
These levels constitute the strategic roadmap for the BIM industry, with the UK mandating level 2 for all projects in 2016.