Building Information Modelling (BIM) is a very broad term that describes the process of creating and managing digital information about a built asset such as building, bridge, highway, tunnel, and so on.
BIM objects are digital desciptions of products or materials that, when combined with other BIM objects, create a BIM model.
A BIM object usually has 3D geometry that describes its physical appearance, as will as data that describes what it is, how it is classified, its performance values, material types, expected lifetime, and so on.
In parametric models, each object need only be defined once and can then be placed in the model in multiple locations as required. If the object is then changed, these changes will appear throughout the model. This makes models automatically consistent and reduces errors.
There are two basic types of object: component and layered.
A component represents building products that have a distinct geometrical shape, such as furniture, windows, doors, equipment, and so on.
Layered (system family/element)
A layered object is a product that does not have a fixed shape or size, such as flooring, carpets, insulation materials, ceiling materials, and so on.
Objects can also be classed as ‘generic’ and ‘specific’:
- Generic (or library) objects are used during the initial design as ‘placeholders’, expressing the need for a specific object to be selected at a later date.
- Specific (or manufacturer) objects are those that represent products specific to a manufacturer.
Objects may be available in specific formats suitable for Revit, Archicad, and so on, and they can be provided in open exchange formats.
The BIM Object/Element Library can also:
- Aid the project team in deciding what information should be included in the model at different stages of the project, and by whom. It can be used for planning and guidance only or to document agreed contractual commitments and responsibilities.
- Incorporate Assets Managers’ CAFM (Computer-Aided Facilities Management) specific parameters, and be used during the design, construction and commissioning stages of the project to record information to be handed over to the facility managers.
- Be used as a reference to ensure that all model object parameters follow a consistent naming convention and reflect industry standards.
“Objects may be available in specific formats suitable for Revit, Archicad, and so on, and they can be provided in open exchange formats”.
An individual object that has unique geometry and does not rely on any other objects to be understood. It carries information about its identity, appearance, performance and usage. Can also carry behavioural information. The object has unique geometry ranging from simple to highly complex.
A component may contain a number of variants to its parameters; however, any variation to the geometry of a component constitutes a new object. For example, a door, chair or light fitting.
Note: A component object:
- Can be aggregated together with construction material objects to form an assembly, e.g. a room
- Is an individual building element that can be reused. For example, doors, stair cores, furniture and internal room layouts, façade panels
Component objects are typically inserted and moved/rotated into the required position.
The term component is sometimes referred to as instance, occurrence or element.
A composite layered object with simple to medium geometry and a range of parameters.
A layered object may consist of one layer e.g. waterproof membrane, insulation, metal decking or consist of a number of layers combined to for a multi layered object.
A multi layered object is often used where it is more practical to model multiple layers together rather than model each separate layer individually.
May carry information regarding identity, performance and appearance. Material may be assigned a specific colour, surface pattern or designated render appearance and specific line work for 2D representation to control the outward appearance of the construction product or geometrical representation in graphical views.
Materials can be used on their own as finishes and coatings, as building products within an object, or to represent an option within an object.
The term material is often synonymous with building material, construction material and surface.
Data used for the description and management of documents and other containers.
Note: Each item of meta-data resides in a field. Codes are the values allowed for fields.
ISO 12006-2: A product intended to be used as a construction resource.
IFC defines a product as a physical object (manufactured, supplied or created) for incorporating into a project. It may be physically existing or tangible. A product may be defined by shape representations and have a location in the coordinate space.
A collection of objects to form a system.
A group of components or types to enable the reuse of standardised design or specification elements improving productivity of design and delivery as well as providing a location to hold specifications and lessons learnt in a simple and useable way.
Local BIM Data Library
If a BIM Object/family Element library can be made available to develop the BEP (BIM Execution Plan.)Currently there is no official South African BIM Object Library available, although there are various libraries available to select from.
- Africa BIM Library https://www.africabimlibrary.com/en/
- BimLocal® www.bimlocal.co
- BimBakery® www.bimbakery.co
- BimSpec® http://bimspec.co/