BIM files: the main BIM formats for design

BIM files are types of file formats containing 3D models with various kinds of information (costs, time, thermal properties, etc.). Here are the main formats and how to view them

The AEC industry is rapidly moving towards the implementation of BIM which is progressively replacing CAD files with different BIM file formats.

BIM (Building Infomation Modeling) is a methodology that allows you to create the 3D model of the work but also to manage all the information associated with it (costs, time, thermal and acoustic properties and more). Therefore , BIM files, unlike CAD files, must allow you to go beyond 3D, allowing you to view all the other information in the project.

CAD and BIM files: what are the main differences?

CAD stands for computer-aided design and refers to the use of computer technology to generate 2D and 3D files which essentially contain simple lines and polylines. CAD effectively replaces traditional hand-drawing processes with automated tools that can help create projects faster and of higher quality. The most popular CAD file formats are:

DWG: This format is almost universally accepted by most visualization/modeling programs and is editable by any CAD-based program (Autodesk AutoCAD , Graphisoft ArchiCAD, Bentley MicroStation, ACCA Edificius and Nemetschek Allplan)
DXF: A format which is very similar to DWG but slightly larger in size. It is a commonly accepted format on most platforms.

In recent years, CAD has progressively been overtaken by BIM, as it offers architects, contractors and engineers the possibility to work together during the project, using the same database and the same building model. The difference between a CAD and BIM, therefore, doesn’t consist simply in 3D modeling, but in a new way of understanding the design and execution phases of the works.

BIM goes beyond simple 3D representations allowing us to create an interdisciplinary digital model of the entire structure which can be shared with a wide range of additional datasets relative to geometry, materials, supporting structures, thermal characteristics and energy performance aspects, through to plant systems, health and safety costs and asset maintenance.

With the increasing use of the BIM methodology in the construction world, it is increasingly frequent among professionals therefore the use of different BIM file formats.

What are BIM files?

BIM files are file formats that contain information-based templates that are shared between different inter-disciplinary professionals involved in the design and construction processes.

There are many ways in which data can be handled in a BIM workflow, and as a result, many different file formats can be used. The variety of formats is closely linked to the tools and platforms used in a BIM process and the purpose and level of detail of the information contained.

BIM file formats are divided into proprietary and non-proprietary file formats.

BIM file format: proprietary formats and open formats

Proprietary file formats are readable only by your software and other permitted software. This use of proprietary formats can hinder interoperability if project team members use different types of software. Among the main proprietary formats we have:

RVT: this is Autodesk’s proprietary format for Revit files and can only be opened in Revit and is used to design and document building structures, floor plans, walls and other elements, analyze the performance of the building, view its structures and collaborate between different teams;
PLN: this is Graphisoft’s proprietary format for ArchiCAD files and contains 3D models used by architects to design building, interior, exterior and landscape structures complete with data related to the structure’s lifecycle;
NDW: this is Nemetschek’s proprietary format for AllPlan files and contains the data of a 3D model of an architectural structure or building, complete with all its measures, constraints and interconnections;
EDF: this is the proprietary format of ACCA software for Edificius files and contains information on various aspects of an entire project: materials, width, inclination of the various elements of the building, GANTT charts, photorealistic renderings and video tours of the project;
NWD: This is Autodesk’s proprietary format for Navisworks files that are used to display 3D building models or structural projects, for interference analysis and detection, and more;
EDL: this is the proprietary format of ACCA software for EdiLus files containing designs of reinforced concrete, masonry, steel and wood structures and used for structural calculation of buildings, analysis of results and detection of interference, creation of work plans and detailed documents.

Open-ended BIM file formats are formats for which the structure is known and are therefore vendor-independent, which means that they can be read and edited by any type of software and thus promote interoperability and collaboration among team members.

Among the main open formats we mention:

IFC: Industry Foundation Classes (IFC) is the most common non-proprietary format for BIM. It’s an open, neutral file format that contains a model of a building or structure, including spatial elements, materials, and shapes. The IFC file format is a software-independent format and can be opened by numerous programs (some of which are also certified by buildingSMART) such as Revit , Navisworks, Edificius, Allplan etc.
ACCA software has the most BIM software certified by buildingSMART, providing an additional guarantee of reliability and consistency to IFC data exchanges
COBie: Construction Operation Building Information Exchange (COBie) is a non-proprietary data format that allows you to share resource data rather than graphical/geometric data. It’s used to transfer data and documents created during design and construction to end users or facility managers.

How do you open BIM files?

Are you collaborating in a BIM process and have you received a file format not supported by your software? To open a BIM file you have two main options:

buy expensive BIM software that supports that specific BIM file format;
use a free online BIM viewer that can open and manage all popular file formats such as DWG, RVT, DXF, EDF, SKP,IFC, and others without the need to have specific software.

Choosing to use a BIM viewer in addition to being advantageous from an economic point of view allows you to:

optimize the collaborative aspect: you can federate in a single shared model different models of different native formats (Edificius®, Revit®, ArchiCAD®, Allplan®, Tekla®, AutoCAD®, SketchUp®, 3D Studio Max® and many others);
maximise interoperability: professionals working with different software can coordinate and collaborate efficiently without any data loss;
create efficient BIM workflows and optimally organize project activities in terms of costs and time, with a significant reduction in errors.