A building information model that includes 3D geometry, such as a CAD (computer-aided design) model, but also adds additional information. Additional information can be material, part numbers, construction details, cost, and other non-graphical data. It can also be functional or process information.
A BIM model falls between a CAD model and a digital twin in terms of the type and amount of information it contains.
While a CAD model can convey information from the design phase through the construction phase, richer BIM models can convey information during the building management process to owners, facility managers, and maintenance personnel.
Popular BIM applications include Autodesk's Revit and Graphisoft's Archicad.
BIM offers these advantages over CAD models:
Reduced project costs.
Less confusion.
Less waste and rework.
Top-down use of design (for ease of delivery, lower operating and maintenance costs, etc.)
The advantages of BIM depend on the principle that putting information that is available to the architect or engineer during the design phase into the model of a building can be extracted by others later, first by those who build it, second during handover to the owner, and third by those who operate and maintain it.
For example:
General contractors could extract exact construction materials and quantities more accurately than if they were counting pieces on a screen or drawing.
Building renovations may require structural knowledge of the building, which would be removable if structural steel were inserted into the model.
Maintenance personnel could find service schedules for the HVAC because the BIM model would have model names and numbers.
However, some of the advantages claimed by BIM are only possible if the BIM model co-exists with other technologies. For example, the claim of “less confusion” because everyone is on the latest version of the model is only possible with version control such as provided by a product data management system or the model is shared from a central source, such as the cloud. “Less rework,” as a result of fewer conflicts, is possible because BIM software uses solid modeling.
DISADVANTAGES
BIM models take longer to set up. Because BIM models contain more information, design firms must take into account the time it takes to input the information.
BIM software is also more expensive than CAD software.
BRIEF HISTORY
The concept of BIM first appeared in a professional commercial CAD program with Archicad, so most CAD experts consider Archicad to be the first BIM program. However, Graphisoft referred to their model as a “virtual building” or “single building model.” Bentley referred to their model as an “integrated project model.” In 2002, Autodesk published a white paper titled “Building Information Modeling” and thereafter put their strong marketing muscle to work, leading to the rapid adoption of Revit in the U.S. and the origin of BIM becoming associated with Autodesk.
However, the origins of BIM date back to 1960, when visionaries coined the term, before any computer could make BIM useful for conventional architects.
The first rudimentary BIM software applications appeared in the 1970s, such as Chuck Eastman's Building Description System, RUCAPS, and Sonata. However, their rudimentary interfaces and the cost of computer equipment limited their adoption. Here is a basic timeline:
1987-Graphisoft launches Archicad
1992 - GA van Nederveen and FP Tolman were the first to specifically use the term "Building Information Model".
In the mid-1990s, BIM software for PCs emerged and, for the first time, architects had access to it.
2010s: National and international governments began to mandate or encourage the use of BIM in public projects.
Today, BIM is widely used throughout the construction industry, especially by large companies in the US and Europe.
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