3D BIM: Definition, Modeling and Software

BIM as a concept has drastically changed many aspects of the AEC industry, and its adoption rates continue to grow. Most construction contracts and projects are now planned with at least some form of BIM in mind. However, BIM is far too complex a methodology for everyone to be able to adopt it from scratch. As such, there are plenty of cases in which only the most fundamental advantages of BIM are utilized, whether it is the common data environment or the use of BIM software to generate models without sharing them with other parties.

BIM itself is a sophisticated process that allows for improved communication, seamless information exchange, and easy collaboration between stakeholders. BIM efforts rely on designated BIM models, the centerpieces of proper BIM projects that act as centralized data sources.

Concept of 3D modeling

3D modeling as a whole is a somewhat universal concept that is more than just a part of the BIM methodology. 3D modeling is the ability of computer hardware and software to produce three-dimensional digital representations of objects and structures. It is used in many different industries, including film, gaming, and architecture.

Creating a suitable 3D model can be a surprisingly daunting task that even the industry’s most seasoned veterans may struggle with occasionally. Accuracy is the key here: since the model will act as a reference point for all project-related tasks in the future, even a slight miscalculation on the designer’s part may create many issues down the road.

There are several different ways to simplify this process. The first step is to determine the target audience for the model, since different professionals require differing levels of accuracy for their work. Determining the project’s overall scope is a good idea, as well, since this directly affects the model quality necessary for the task.

3D modeling vs BIM

The idea of 3D BIM is not as direct and self-explanatory as one might think. There are plenty of differences between BIM and simple 3D modeling, and we would like to go over them before diving into the topic of 3D BIM.

Building information modeling is a data-rich representation of the functional and physical characteristics of a facility in digital form. It offers not just geometry but also comprehensive information about every object in the structure, including its material specifications, maintenance requirements, energy performance, and cost data.

3D modeling, on the other hand, is the process of creating a three-dimensional geometric representation of a structure or structures. 3D modeling in the context of the construction industry is the process of generating visual models representing the appearance and physical dimensions of a structure without the embedded data that BIM models provide.

Since 3D models serve as the baseline for the creation of BIM models, it is not difficult to see how many of the features of 3D models are also present in BIM models, including visualization, geometrical accuracy, and so on.

However, there is also the fact that BIM models are usually far more complex in comparison. They cover the entire project lifecycle while providing a bigger scope of application, offering more depth in terms of information, and even providing some collaborative capabilities. The increase in complexity is a noteworthy disadvantage, but the majority of users admit that it is more than worth the effort.

3D BIM modeling

3D BIM is the most popular “dimension” of BIM so far. The concept of BIM dimensions expands the sophisticated nature of implementing BIM and allows for multiple integration phases to be segregated and visualized. 3D BIM represents the ability to present a digital version of a present or future asset as a model that can be shared with other project participants.

BIM dimensions

The concept of 3D BIM implies the existence of a common data environment that hosts a variety of project-related information within a three-dimensional model. This information is both geometrical and non-geometrical, providing an extensive overview of the structure in its “as-built” state.

The topic of “information” can be expanded further with other BIM dimensions, including:

• 4D BIM, representing all time and schedule-related information, including project timelines, Gantt charts, etc.
• 5D BIM, a showcase of cost-oriented data, including cost management processes, estimation calculations for budgets and material costs, and more.
• 6D BIM, representing all kinds of sustainability and environmental data, such as economic impact studies, environmental impact analysis, etc.
• 7D BIM, acting primarily in favor of facility management and encompassing scheduled maintenance and other similar operations.
• 8D BIM, covering the issue of on-site safety by providing detailed capabilities for the simulation of potentially harmful events or accidents on-site.

It is worth mentioning that every additional dimension of BIM includes all of the previous ones by default. That way, attempting to implement 5D BIM in the context of a specific business would have to cover not only cost-oriented information but also time and schedule data.

Data synchronization and collaborative workflows

BIM also excels in assisting with the synchronization of data between disciplines, such as mechanical, electrical, plumbing, and others. Being able to communicate every change in the structure of the project to all stakeholders in an easily digestible 3D model reduces miscommunication and rework, boosting overall collaborative efforts. The ability to perform processes such as clash detection and issue tracking greatly simplifies certain aspects of the design phase.

The concept of 3D BIM also entails the existence of a common data environment that hosts a variety of project information within a three-dimensional model. This information is both geometrical and non-geometrical, providing an extensive overview of the structure in its “as-built” state while also going beyond the traditional visual information most 3D models offer by default.

This integrated approach to data management changes the way project teams interact with building information, with real-time synchronization being one of the most prominent advantages. The ability to update all related documentation whenever there is any change to an element of the project ensures that architects, contractors, and other stakeholders always have the most up-to-date version of the project to work with, thus eliminating the possibility of the use of outdated information.

BIM’s common data environment capabilities act as a centralized hub for all project participants to access, modify, and otherwise interact with all kinds of project information. Cost estimates, sustainability ratings, technical specifications, maintenance schedules, and material properties are just a few examples of such information. The incredible level of data integration dramatically improves the quality of decision-making throughout the project’s entire lifecycle, from early design to post-construction use.

Additionally, BIM is far more than just a file sharing environment, offering simultaneous multi-user access, version control, and many other features. We should also mention clash detection here as a separate aspect of the collaborative framework created by BIM, offering the automated ability to identify spatial conflicts between objects and systems in the BIM model. This is a proactive approach to conflict resolution that dramatically improves quality control in any construction environment without losing overall project momentum.

The BIM software market is large and extremely varied, with several sub-categories of software being extremely popular in their own situations. While there are many solutions that offer the entire set of BIM capabilities at once, there are also plenty of solutions that specialize in the communication aspect of the environment with extensive feature coverage to compensate. For example:

• Revizto is a tremendous issue-tracking and clash detection solution with extensive collaborative features. It offers integrated communication tools, cross-platform accessibility, and support for a variety of data formats.
• Autodesk Construction Cloud is a multifaceted solution from one of the most renowned software providers in the construction industry. Its BIM capabilities are directly imported from another solution previously called BIM 360, which offered cloud-based project management capabilities with real-time model coordination, document management, version control, and more.
• Trimble Connect is a popular cross-platform collaboration solution with model viewing capabilities, a task management feature set, an issue tracking function, and much more. It can easily be integrated with many design and analysis tools while also being able to operate by itself, as well.

Data-driven decision-making in BIM

Generally speaking, the data-driven approach of BIM dramatically improves the convenience of working on construction projects, which is an industry known for its complexity and large number of collaborators per project. This significant shift in construction management methodology provides a large selection of benefits in different aspects of construction projects.

Predictive modeling and performance optimization are good examples of this, and they are made possible by the integration of data analytics capabilities in BIM. Historical project data analysis makes it possible to optimize resource allocation and forecast future bottlenecks while leading to better decision-making in construction sequencing.

The quantitative nature of BIM data also provides an unprecedented level of precision in tasks such as quantity takeoffs or cost estimation, with many of these quantity calculations performed in an automated manner. The ability to reduce human error in budget forecasting and material ordering is a massive advantage for practically any environment in the industry.

We can also say the same for other aspects of the construction process, such as data-driven sustainability analysis, extensive project scheduling, and so on. The systematic data collection and analysis in BIM models generates a massive number of actionable insights for future projects, providing a library of best practices and solutions to common issues in a knowledge management system that gets more efficient the more projects it goes through. This incremental learning contributes to significant improvements in both methods and outcomes of project delivery.

Advantages of 3D BIM

3D BIM is often treated as a “complete” implementation of BIM that offers a lot of what BIM as a concept stands for. As such, it can be somewhat difficult to implement, but the number of potential advantages is just as impressive:

Clash detection

The ability to replace the manual cross-referencing process of detecting clashes between drawings with an automated, customizable sequence is one of the biggest advantages of BIM. It is faster than manual methods and also offers a number of useful features on top of that, such as customizable notifications, priority systems for flagging mechanisms to note the most significant clashes, and so on. The ability to detect clashes proactively dramatically reduces the total cost of a project by removing the need for expensive rework on-site if clashes are not detected beforehand.

Digital twin

A “digital twin” is a virtual replica of an asset that can evolve through different phases of the structure’s lifecycle. A “digital twin” is an evolution of a BIM model that shines in post-construction building management by being able to monitor building performance, simulate maintenance scenarios, and access real-time operational data from on-site sensors and other devices. Maintaining this kind of model alongside its real-life counterpart dramatically improves the quality of decisions about future renovations, space utilization, energy management, and more.

Environmental analysis

The massive amount of information stored in an average BIM model helps dramatically with sustainability improvements due to the ability to perform detailed calculations for daylight effectiveness, energy consumption patterns, carbon footprint impact, and so on. All of this is possible by running a multitude of simulations on the existing virtual models, making it drastically easier for architects and engineers to optimize factors such as building orientation or material selection to meet sustainability targets.

Data centralization

Data centralization is another advantage of BIM environments that completely erases the issue of data fragmentation, which has been present in the construction industry for decades. The ability to store all information in a single, coordinated model makes it easier for every stakeholder to work only with the most up-to-date information possible, removing the possibility of mismatched data versions or outdated documents being used for important tasks.

Issue tracking

The issue documentation process has practically been remade from scratch with the introduction of BIM. Now, team members can document and resolve issues using systematic digital workflows in a centralized environment, greatly improving both the performance and convenience of such efforts. The ability to create a clear visual record of each issue in the BIM model improves accountability while providing valuable insights for future efforts thanks to the existence of a searchable history.

Collaborative advantages

Collaboration is an important cornerstone of BIM, the influence of which can be seen in most of the advantages above. The ability to break down traditional data exchange silos between project teams is a tremendous advantage over legacy cooperation methods, and real-time coordination in a shared virtual environment can improve total project performance in the form of reduced RFIs, enhanced decision-making, and the ability to receive input from various contractors and specialists early on.

Challenges of 3D BIM

Building information management is a methodology that spans the entire process of project realization from start to finish. It is only natural that such a massive process would have its own share of challenges and disadvantages, even if the overall number of advantages more than makes up for the disadvantages:

• The steep learning curve is one of the first and most prominent disadvantages of 3D BIM. Getting into the field of 3D modeling is difficult enough, and BIM as a process expands upon the concept, making BIM extremely challenging by design.
  • While BIM is challenging software in most cases, there are not many options when it comes to resolving this issue. The inherently complex nature of BIM prevents most solutions from making themselves user-friendly without risking parts of their feature set. As such, a commitment to user training is the most suitable solution for this issue.
• The inevitable increase in the complexity of data is an advantage that not many people talk about, but the sheer complexity of the information that an average BIM solution works with can make collaborating and sharing data with other, less advanced companies and solutions challenging.
  • This complexity is not something that can be resolved overnight, similar to the steep learning curve. The only credible solution is to invest in thorough user training in order for most users to be able to comfortably use BIM software with ease.
• The BIM software market as a whole is very fragmented, and there are many different BIM solutions with their own file formats. This kind of fragmentation makes collaboration between different software variations more complicated than it might be, even though there are a few technologies that aim to solve this issue, such as the existence of the IFC file format.
  • Aside from the aforementioned standardized data formats, such as IFC or COBie, there is also the option of choosing a BIM solution that is guaranteed to work in some capacity with most project participants. Revit is a good example of such a solution due to its sheer popularity.

How 3D coordination works in the context of BIM models

Coordination is one of the main goals of BIM. It allows different team members to work with the same 3D model without interrupting each other, creating a single 3D BIM model that includes all of the changes and modifications made by different contributors.
The introduction of BIM software can significantly simplify this process, but it is still difficult to deal with. There are plenty of challenges to deal with here, including the issue of updating the model with each subsequent change. This issue is not easy to solve, especially when there are multiple team members working with entirely different elements of the model.

Luckily, a proper BIM execution plan combined with a versatile common data environment can make this issue much more manageable. The same goes for the issue of conflicts between the changes that different project participants make. It can be solved by implementing a competent BIM solution that either alerts users about potential clashes with other people’s work (clash detection) or even resolves the issue automatically (Revizto is an excellent example of a solution that can do so).

Role of 3D BIM in lifecycle management

The BIM methodology extends beyond 3D visualizations, offering a collaborative environment with dynamic project management capabilities spanning every major phase of project realization, from early design to eventual decommissioning.

Planning phase

BIM makes it possible for project teams to conduct detailed feasibility studies, making use of a vast amount of information to evaluate many design scenarios. The parametric modeling capabilities also simplify rapid testing for some of the smaller elements of the model without compromising the design integrity and building code compliance.

Design phase

BIM’s intelligent data management simplifies design decision-making thanks to its ability to showcase the cascading impact of every decision in the context of the BIM model. This showcase provides not only material quantity numbers and structural load calculations but also cost estimates and even clashes with other objects where applicable.

Construction phase

The construction phase relies a lot on scheduling and cost calculation capabilities in order to optimize project delivery. There are also features such as complex construction sequence simulation, real-time progress tracking, automated quantity takeoffs, and even precise financial control thanks to the ability to track costs accurately.

Post-construction phase

Operating as comprehensive asset management solutions is another use case for BIM models in the post-construction phase. A BIM model is a great facility management database filled with equipment specifications and installation details, among other things. It can streamline building operations and even serve as information storage for future renovation decisions thanks to its ability to link maintenance schedules, performance data, and warranty information to specific components.

The existence of a continuous digital thread throughout the lifecycle of the project provides a number of advantages we have gone over above, including better forecasting, improved issue resolution, better maintenance, enhanced sustainability, and so on.

Basics of the 3D BIM modeling process

There are several different approaches to starting with 3D BIM modeling. The obvious option is to learn the 3D modeling process itself in the appropriate software with basic references. However, if the project is not about creating a structure from scratch, then it might be best to use a digital copy of the existing building plans as the baseline.

Once the plans are scanned and digitalized (if they were originally in physical form), then it is time to begin with tracing the walls and adding detailed information about every aspect of the structure. This is a great way to learn 3D BIM modeling, since a proper building plan includes all the necessary dimensions.

It is also a great way for pre-construction teams to double-check existing building plans (if they have not worked with BIM software before). Once the model is complete and filled with all the geometric information, it can be used to expand the existing data scope by adding schedules, quantities, costs, resources, and other data that is necessary to go “above” 3D BIM. A more comprehensive view of the construction project can be created this way, simplifying the process of identifying various issues with the building before the construction phase.

Tips for improving the accuracy and performance of 3D BIM models

Accuracy is one of the most important parameters of a 3D model. There are many issues that might affect this parameter, starting with the scope of the project.

There is a commonly accepted standard when it comes to the detail of BIM models, called “level of detail” (LOD). It helps identify how detailed the model must be. The commonly accepted curve ranges from LOD 100 to LOD 500, with six separate levels:

• LOD 100 – Conceptual representation with basic information, mostly used in early-stage planning.
• LOD 200 – Approximate geometry that contains slightly more information with approximate quantities of size, shape, location, and some non-geometric information.
• LOD 300 – Precise geometry that uses accurate dimensions, suitable for generating traditional construction documentation.
• LOD 350 – Addition of interface details between systems, such as connections, supports, interfaces, etc.
• LOD 400 – Fabrication-level detail for assembly purposes, and also comes with an extraordinary number of details that would be enough to perform either assembly or fabrication with this data alone.
• LOD 500 – As-built verification of actual construction with verified field conditions, suitable for facility management tasks such as maintenance or renovation.

Being aware of who benefits the most from the model is a good way of gaining a better understanding of the model’s scope. The same could be said for the model’s intended use. For example, manufacturers’ products are usually less precise than complex systems that have to be created from scratch using fabrication-level drawings.

Once both the scope and the purpose of the project are determined, it is time to start working on more specific details. Accuracy is still the king here, especially in the early stages of model development, considering how many changes will have to be made if mistakes are discovered later on.

Step-by-step guide to start 3D BIM modeling

The typical process of creating a 3D BIM model once you have at least the basic level of modeling capabilities includes the following steps:

1. Defining the goals and scope of the project, including the primary purpose of the BIM model and the expected level of detail (LOD).
2. Gathering existing information, such as building plans, sketches, digital files, and physical plans if they exist (this stage is where these plans should be digitized).
3. Choosing the appropriate BIM solution to work in, choosing specific software that meets the needs of your project.
4. Setting up a common data environment to act as a centralized platform for storing and sharing project information for improved collaboration efforts.
5. Starting work on a basic 3D model, with a geometrically accurate representation of structural elements such as floors, roofs, walls, etc.
6. Adding non-geometrical data, such as equipment details, material specifications, etc.
7. Testing for accuracy on a regular basis to ensure alignment with all project requirements.
8. Collaborating with a high degree of efficiency using a CDE with real-time update capabilities, clash detection, and seamless coordination across disciplines.

Asking for help is also a good idea in most cases. There are many designers and engineers who have at least some insight into 3D modeling software, making them a goldmine for most beginner 3D BIM modelers, with a variety of tips and insights.

We should also mention that there are a number of common pitfalls in 3D modeling that revolve solely around project accuracy, such as:

• Model inconsistency issues create a lot of confusion and errors in construction documentation due to varying levels of detail, naming conventions, or modeling methods.
• Version control issues arise when there is no proper data synchronization workflow in place, resulting in conflicting changes, lost work, and the use of outdated information. The size of the issue scales with the size of the project and its complexity due to the larger number of parties that need to work within the same model simultaneously.
• An over-modeling issue is the result of a higher level of accuracy being implemented early on, which leads to a waste of resources and has the potential of making the entire model more difficult to work with at every subsequent stage of project realization.
• Data quality issues are relatively common due to the average complexity of the process, with common examples being inaccurate material specifications, incorrect parameter information, inconsistent units of measurement, etc.
• Software or hardware limitations represent a lack of understanding of the limits of a company’s capabilities in specific circumstances, leading to performance issues, file size management issues, compatibility issues, and even data loss during data exchange.

Conclusion

3D BIM is the best-known “dimension” of building information modeling. It represents the capability of a complex 3D CAD model to interact and integrate with the massive amount of information that a BIM solution can provide in a centralized manner. There are many different 3D BIM solutions to choose from on the market, and not all of them have to have complex CAD capabilities to be considered 3D BIM solutions. The most important factor for these solutions is to be able to create a convenient collaborative environment, and different solutions achieve this goal in different ways.