The largest hurdle with any scan-based project is hitting the sweet spot of detail — between having too much and too little detail. A model that has all scan points over consumed is going to bog down the software, which might impede the workflow; conversely, if a model has too little detail, it may not be precise enough for fabrication or facility management. This paradox illustrates the challenge of reality capture: when it seems that we have the capability to capture every last inch of a building, most of our projects only see a portion of that captured information.
It all comes down to Level of Development (LOD). In Scan to BIM 3D modeling, LOD doesn't refer to geometrical difficulty or file size, but rather how reliable, accurate, and suitable a model element is for its intended purpose. Whether that purpose is for conceptual design, coordination, or as-built documentation, LOD ensures that the model meets the project's purpose rather than simply being an increased burden.
This guide is simply the organized process to define, produce, and validate suitable LOD for your scan-based project. By considering the right detail instead of maximum detail, you can efficiently create models that are clear, have value, and even leave a legacy in every model you create.
The concept of the Level of Development (LOD) is essential when producing Scan to BIM models. LOD defines how much detail, accuracy, and information a model contains to satisfy the project requirements without overloading the teams with irrelevant information.
Hence, choosing the appropriate LOD in Scan to BIM workflows gives 3D BIM modeling the appropriate level of accuracy, usability and efficiency for the project lifecycle.
Getting the right Level of Development (LOD) in Scan to BIM and 3D BIM modeling is not about being hyper-detailed; it is about creating the right model for the right purpose. The following is a practical, structured workflow that will lead to accuracy and usefulness to avoid over-complication when scanning and modeling are placed within the digital twin context (involving planning, going to site, scanning/creating a digital model, then using the digital model in a varying capacity).
Every project starts with understanding of purpose. When we talk about Scan to BIM, it is imperative to identify the intended use of the Scan to BIM model before modeling begins. For example, for a renovation project, you may produce details of geometry for structural and MEPF coordination while a retrofit may just need only layout of the major systems. For facility management models, the intent assumes future capacity that its usefulness will be made in a longer-term capacity (with asset data attached), while for models developed for clash detection and coordination, the goal will be accuracy of geometry.
When determining LOD goals with stakeholders, you can avoid both under-modeling and over-modeling when you ensure these goals are based upon that stakeholder's needs. Establishing alignment early on helps ensure that the model gives maximum value without unnecessary efforts. This is simply the foundation upon which all future modeling decisions will be measured against.
Simply put, the quality of your Scan to BIM model is only as good as the point cloud data it is built off of. Check the quality of the scans - is there completeness, coverage and resolution? Unwanted voids, misalignments and noise will impact the overall accuracy of the modeling and ultimately the final BIM, and all elements downstream.
Addressing this upfront, whether it is cleaning the scan data or working with the survey team to figure out an appropriate way to coordinate a rescan, will save time and unnecessarily costly revision down the line. A clean, valid point cloud is the foundation for accurate modeling and workflow efficiencies moving forward across project disciplines.
Not every project is going to need the same detail. For example, LOD 200 is sufficient for conceptual planning and early design, while LOD 300 has enough detail to allow good coordination among all disciplines. LOD 350 goes a step further and models interfaces and supports for constructability. LOD 400 requires fabrication drawings of level of accuracy, and LOD 500 is as-built conditions with verification in the field or revealed conditions.
The determination of which LOD to start with will be dependent upon project scope, budget, and schedule. Overly modeling can use resources needlessly and negatively impact software efficiency, while modeling too little of the requirements can lead to construction errors and missed deliverables. The right balance is important for total efficiency and usability.
When the LOD has been defined, it is important to provide consistency throughout the project. This is where a BIM Execution Plan (BEP) plays an important role. A BEP outlines the modeling standards, file structure, naming conventions, and tolerances so that everyone on the project team can be aligned.
By establishing the standards, this also allows the architectural model to function with the structural model and the MEPF models. If there are unclear standards, teams are likely to miscommunicate, rework models, or create discrepancies in deliverables. A solid BEP will ensure that everyone is on the same page and also ensure that the final model will meet the levels of quality previously established.
You should not think of modeling as a one-off or one-and-done effort. Instead, the modeling process should be iterative. You will develop components of the model in a sequential or staged fashion by discipline, starting with the primary structure, layering on the architectural components, and then the MEPF elements. The objectives are to find errors early in the project and avoid coordination between disciplines.
Validation is also critically important. Consistently overlay against the point cloud to validate placement and run clash detection regularly to find conflicts. Each iteration should be QA to mitigate costly start/rework and ensure ongoing compliance with the project.
A Scan to BIM project is not complete unless the stakeholder requirements are met. During the modeling process, you should share progress models for review. These interim checkpoints allow for the project Architect, Engineers, Contractors and Owners to provide input and request any necessary and reasonable changes before the model continues to different levels of LOD.
Completing this continual review process helps align the project with its goals and build stakeholder trust and transparency. Stakeholders have the opportunity to see incremental changes to the model and can confirm how effectively the model meets their needs. Getting stakeholders onboard early on, helps to minimize levels of disagreement or dissatisfaction upon handover.
This final step is about ensuring completion and accuracy. Conduct a thorough QA/QC process to ensure that the geometry is correct based on the point cloud, the parameters are produced correctly, and the model meets the acceptable LOD specified. Also check tolerances, metadata, and other project schedules that are linked in the model.
Once validated, you can export the deliverables in the required format (e.g., Revit for design, Navisworks for coordination, IFC for sharing in open-standard formats). Deliver the model with any 2D drawings, schedules, and reports, as required by the project scope. Also remember, a model presented in its historical context is a reliable asset for the future use for operations and decision making, not simply a deliverable.
Scan to BIM and 3D BIM modeling provide unrivalled accuracy and efficiency on a project, but establishing and adhering to the requisite Level of Development (LOD) has its challenges as well. Teams may encounter obstacles that, if not resolved early, can jeopardize construction schedules, budgets and the final outcome.
The challenge is achieving the right amount, as it's about including only the level of detail required to fulfil its intended function.
Either way, there can be disputes, delays, and costly reworks due to either party being misaligned in their expectations.
You run into financial strains, as well as sinkhole ROI, when you fail to consider the budget and schedule constraints before the schedule is established.
Therefore, the top challenges boil down to clarity, alignment, and resource optimization. Addressing these challenges at the front end of a Scan to BIM project will give clients confidence that the LOD (Level of Development) they chose brings value and not inefficiency.
Getting the appropriate Level of Development (LOD) when working in a Scan to BIM or a 3D BIM environment to Model is more than just a technical ability, it's also communicated with a disciplined process that addresses planning, implementation, and collaboration through all project phases. The following best practices will improve efficiency and dependability to workflows associated with scan-based projects:
By implementing these practices, project teams can have the greatest benefit from Scan to BIM workflows, delivering accurate, efficient, and meaningful 3D BIM Models.
In scan-based work, achieving the appropriate Level of Development (LOD) is really about being accurate to the level you need, not just creating detailed models. By determining your objectives, confirming the quality of the scan data, and choosing the appropriate LOD level for the work, the project team should be able to avoid over- or under-modeling the project. By working within a structural set of standards for creating models, validating iteratively, and keeping stakeholders on track with the operational benefits of design data, it is possible to keep models accurate, efficient, and beneficial throughout the life of the project.
When implemented with a good amount of thought and consideration, the outputs of Scan to BIM and 3D BIM Modeling really produce reliable models to be used through design, construction, and facility management that can be put to good use without wasting time or resources. Appropriate resolutions in the LOD strike an appropriate balance between modeling clarity, concise cohesive data output, efficiency, and long-lasting usability of the data.
Rian Voss is Marketing Head at ScanToBIM.Online, which specializes in Scan to BIM services for commercial and industrial projects. With deep expertise in 3D laser scanning, BIM modeling, and project coordination, he helps AEC professionals optimize workflows, minimize rework, and achieve data-driven results. Rian is excited about using technology to improve construction and facility management for a smarter, more efficient future.
Have comments or feedback on this article? Visit its AECbytes blog posting to share them with other readers or see what others have to say.
AECbytes content should not be reproduced on any other website, blog, print publication, or newsletter without permission.
