A BIM object is a digital representation of a product or material. The BIM object consists of 3D geometry and metadata or properties that describe the type of object, its material, classification, performance, lifetime, and so on.
BIM objects are essential to the development of BIM. Indeed designers and other construction companies can not model all the objects of their digital models. It would take too much time and designers do not know all the design details. That is the reason why, these objects must be available, either in generic form at the conceptual stage or in a specific form for design or construction. We can make a clear distinction between generic and specific Bim objects.
- Generic objects usually come from libraries delivered with the software, or specialized business, and are used when the exact model, a door, for example, has not yet been defined. We know that a door is needed between two rooms, we already know some parameters, such as the material, the fire resistance, etc., but not the exact model. From then on, a generic object will be used. Generic objects may be used throughout the life cycle of the digital model.
- Specific objects, or manufacturing objects, meanwhile are a virtual representation of a product that exists, for example, a window, which has been chosen and will be installed. All features or properties are therefore available, provided by the manufacturer. These objects are rarely used at the conceptual or early design stages, but if they are, then there is a good chance they will be selected for construction.
Moreover, a clear distinction can be established between component objects and material objects. A component object appears as a piece of equipment or furniture that has 3D geometry whereas material objects, represent building materials where the size of the object is not defined.
In some cases, BIM objects do no have geometry. It can be explained by the fact that the level of detail does not require geometry or because the BIM objects have not been specific yet.
It is also possible to differentiate BIM objects according to their format. Indeed, BIM objects in native BIM tool formats can be imported directly into Revit or Archicad during the design process. Revit BIM objects are used as Revit Families or Archicad BIM objects are used as Archicad GSL objects. BIM objects could also be provided in Open BIM exchange formats, (IFC format) in order to support a wider set of design tools. Ideally, a BIM object should be available both in native formats (Revit or Archicad) and open formats.