What is BIM?
The Building Information Modelling concept (BIM for short) was created by Autodesk – a US software company specialising in digital 2D and 3D design. Renowned CAD manufacturers enables architects and engineers to create and visualise parametric building models using Revit®, ARCHICAD & Allplan – popular BIM programs for architects – as well as to construct and plan in 3D. In order to understand the nature of BIM, it should first be noted that BIM is not itself a type of software, but rather a planning method. When we talk about BIM programs, we are actually referring to CAD software, indicating that the CAD system provider is “BIM ready”. The following example clarifies what BIM means:
In traditional construction planning, the architect uses CAD systems to produce an architectural drawing. These plans are supplied to specialist engineers, authorities, and fire safety experts, among other stakeholders who wish to be kept up-to-date at all times. For architect firms, a constant and considerable priority when designing a building is ensuring that the estimated budget does not get out of hand; costs are calculated based on material quantities derived from estimates based on the drawings. In other words, the geometries are inevitably linked with service components which are defined in monetary terms, as service items are fully listed with details of individual quantities and calculated partial services. But what if there is a change to the floor plan which affects building components such as windows and doors, for example?
In larger projects in particular, changes can continue to arise during the planning phase and often even after construction has begun. When that happens, all drawings must be changed and the quantity measurements adjusted; then all parties involved in construction must be provided with the updated drawings so they can coordinate with the respective technical planning divisions. This amounts to significant additional work and coordination, which also means added potential for error. BIM models address this exact problem. They are used not only to record the geometric structures of a building, but also to store all construction-relevant data and attributes centrally, so that they can be updated if necessary. As such, BIM can be used to optimise building planning to a significant extent, as well as supporting facility management throughout the useful life of the building.