The Scan to BIM series arrived to the modeling stage, and in this article we will highlight the contribution of Autodesk applications provided by Graitec Romania in streamlining information modeling.

After collecting spatial data using 3D laser scanning, the information is imported into Faro Scene, software compatible with the scanner used by the BIM Technologies team. This software allows us to do the first processing of the collected information from the field. First, we merge data from all the scanning stations used for one objective into a single point cloud. Once merged, we then move on to the point clouds organisation into meaningful groups to simplify the work in the next step. For example, separate clusters can be created for each scanned level, exterior stations can also be merged into a single cluster, as can special features for which detailed modeling is required (e.g. monumental interior staircases, balconies with caryatids etc). Faro Scene facilitates 3D visualisation of scanned elements (including colouring of point clouds), sharing or exporting data in different formats for further analysis. Thus, the result of this initial processing is the Laser Scan model, which we then export in .rcp format.

The next stage of the modeling process is carried out in Autodesk ReCap Pro, a software that allows us to visualise and analyse the 3D model from different points of view, to make measurements and annotations of certain features, thus facilitating a better understanding of the captured environment. More specifically, it is a virtual exposure of the reality on the ground, which is useful for both our collaborators and our clients, who can thus keep abreast of the project’s progress in real time. Autodesk ReCap Pro also allows us to merge all the previously defined layers into a single one. The file resulting from processing in Autodesk ReCap Pro becomes the main source of information for the creation of the information model, and is then imported into Autodesk Revit.

Modeling in Autodesk Revit simplifies the process, as it is a software that emphasizes collaborative work and multidisciplinary models, reducing potential errors that can occur between specialties, another advantage for clients.

To start modeling, the first step is to set up the project according to the customer’s requirements. involves establishing the general way of working, defining the model’s level of detail (LOD – Level of Development), creating a central file in a common data environment (CDE). Our team uses Autodesk BIM 360, a platform that allows us to connect project teams and data in real time. This is where files are created specifying the scope of each user by creating separate worksheets, so that the same element is not edited at the same time by 2 people.

Once the working environment is set, we move on to creating the geometric model, i.e. the modeling of the construction elements: walls, floors and ceilings, roof, doors, windows, stairs or decorative elements. Depending on the modeled element, in order to navigate fluidly and efficiently in Autodesk Revit, we switch between the different view available: 2D views (planes, sections, facades) and 3D views (perspectives, axonometries).

Autodesk Revit offers a wide range of tools for creating the different types of building elements mentioned above, which facilitates the modeling process. So, we start by selecting suitable building elements from the Revit family library. After choosing the appropriate family, placement in the model is easily made by setting the appropriate plane and using the alignment and move/rotate tools, which brings accuracy and precision to the modeling process. Element parameters can be adjusted to specify de facto properties (e.g. for walls we can adjust height, thickness, materials etc).

Also, in addition to the predefined elements, we have the possibility to model a custom geometry directly in Revit. We use drawing tools such as lines, arcs, circles and rectangles as a reference for the actual modeling. This allows us to create unique building features or modify existing elements to better match the reality captured in the point cloud data. These newly created features are saved in Revit’s internal library and will be available to us in future projects.

Periodically, as we place elements, we perform a visual check between the model and the point cloud to make sure that the geometry of the elements is exactly in line with the data from the field, that there are no missing or duplicate elements. Autodesk Revit allows the point cloud data to be overlaid directly onto the model for visual reference, so we can accurately match the digital model to the physical environment.

Before proceeding to the next step, the model is reviewed to ensure accuracy and consistency. This geometric model is the basis for further detailing, refining and coordinating of the BIM model throughout the design and construction process.

We therefore continue the modeling process in Autodesk Revit by adding details such as structural components, MEP systems, furniture, accessories or elements typical of other disciplines specific to the objective. Each element is assigned properties and parameters such as: materials, dimensions and configuration, performance characteristics, technical specifications, information that is then used for various analyses or project documentation. This results in the 3D BIM model or information model. Also, by entering up-to-date project data, the evolution of the construction over time can be documented.

As previously mentioned, collaboration between specialties is very important during the modeling process, and Autodesk Revit facilitates this coordination between architecture, structure and MEP. We thus have the assurance that all disciplines are properly integrated and collisions between elements have been avoided/ resolved.

It is essential that the development of the BIM information model is coordinated by a person specifically trained in the field, and our team includes people accredited as BIM Manager.

In conclusion, a 3D BIM model is more than just a geometric model, it contains information generated by all the specialties involved in the project. Although extremely complex, the 3D modeling process can be simple if it is done by a well-trained team that knows how to make the most of the facilities that the modeling software has to offer. Also, throughout the project the client has real-time access to monitor the project’s progress, with the ability to visualise without the need for technical knowledge or a Revit licence, as the Autodesk Construction Cloud platform used for this has an intuitive interface.