Basis and cause of Computer-Aided Design (CAD)

Designers and builders have been trying for centuries to describe three-dimensional (3D) buildings on two-dimensional (2D) paper. Throughout this chain of communication, there have always been differing interpretations of the expected outcome. Describing 3D buildings in a 2D environment results in a trade-off between what is necessary and what is possible.

In some cases, very complicated parts of buildings are described with 3D scale models, smaller models of the building under construction. Architects have used scale models to better understand design results and present them to their clients. Unfortunately, they have very little impact on communication with construction teams because of the low level of detail.

Traditional drawings show dimensions and shapes, while textual descriptions and specifications are used to provide the information required for construction.

The first computers allowed architects to design electronically using CAD (Computer-Aided Design). However, these systems were limited to two dimensions and provided only minor improvements over hand-drawing.

More advanced computers made it possible to create 3D models using an Electronic Building Model called 3D CAD. Shortly afterwards, engineers, contractors, and building owners began to add useful information to the electronic building model, leading to the introduction of the Building Information Model or BIM.

Information is the main driver of a revolution in the construction industry, where information needed in design, construction and maintenance processes is stored and transferred in a new way. Communication among participants in the construction process is a key element of the construction industry worldwide.

Construction projects involve designers, controlling bodies, construction companies, and their broad “sub-levels”. 

Lack of communication can lead to huge losses in an industry which has become highly competitive. As studies have shown the significant impact of technological developments on modes and means of communication in the construction industry, the use of BIM has been required, for example, in the UK in all public procurement projects since 2016.

The historical origin of BIM

The term BIM was not created by software developers. The concepts underlying BIM emerged in the 1960s. In 1975, Chuck Eastman described a working prototype of BDS, (Building Description System), which included ideas for parametric design, the creation of 2D drawings from a model, and the output of volumes.

In 1982, in Budapest, Hungary, physicist Gabor Bojar began developing a program based on the principles of BDS technology.

In 1984, the Radar CH program, later renamed ArchiCAD, was released for Apple Lisa operating systems.

With the significant development of the World Wide Web in the 1990s, the use of web-based document management systems began to spread.

The combination of “Building Information Model” and “Unified Data Environment” became Building Information Modeling or BIM.

In 2000, Charles River Software, a company founded by Irwin Jungreis and Leonid Raiz in Cambridge, created a program called Revit, which made modelling much more convenient and efficient thanks to object-oriented and database-oriented programming.

In 2002, Autodesk acquired the company and continued to develop Revit. Revit revolutionized BIM design by creating a platform in which parametric element families can be created in a visual programming environment.

Since then, many companies such as Autodesk, Graphisoft, Nemetschek, Trimble, Bentley have been working on BIM software development. The development of these tools is unthinkable without user involvement and direct feedback. In effect, companies involved in construction have at least indiretly financed the development of BIM.

Impact of BIM on industry

BIM is not a thing, phenomenon, or type of software. BIM is a Sociotechnical system that includes extensive process changes in the design, construction and maintenance of buildings.

Advantages and disadvantages of BIM

The application of the BIM concept to construction projects brings significant changes to daily work processes. The main advantages are the following:

• more possibilities in project planning and design using BIM;

• faster implementation of project changes → the central object of BIM documentation - model;

• fewer problems on the construction site → in-depth analysis of problems at the design stage;

• material economy → more accurate determination of construction volumes from 3D objects;

• improvement of communication between project participants → availability of visual material from design work;

• support for industrial production and industrialization.

There are also many obstacles and unresolved shortcomings. The main ones are the following:

• a definition of contractual obligation and payment for the creation of BIM content;

• a lack of compatibility between those involved in the project;

• the inability of state institutions to adapt to the opportunities presented;

• software costs;

• a lack of knowledge and lack of appropriate specialists;

• the complexity of IT systems, which can become difficult to control.

BIM challenges

Although the introduction of BIM practices solves a number of shortcomings in 2D design, it also brings new challenges:

1. inadequate definition of the task → different interpretations of the details and content of the tasks;

2. confidence in the data provided by the model, without a quality control mechanism → unpredictable deviation of construction volumes from actual volumes;

3. the use of different authoring programs → additional work needed to meet common standards, such as the IFC transfer standard;

4. implementation problems → the implementation of BIM requires an understanding of new processes and appropriate project management approaches, not just software implementation.

BIM modelling

The main difference between CAD and BIM design is the use of object-based, parametric modelling, which was originally developed in the 1980's for production.

BIM software companies have defined the main building object categories, which were then standardized using IFC object classes. BIM design authors provide the ability to combine 3D objects with 2D drawing information, allowing the use of a certain degree of 3D detail while maintaining the ability to develop a complete drawing.