Stefan Larson, founder and CEO of BIMobject explains the process and benefits of representing manufacturers’ products as BIM components
Unlike product manufacturing, where 3D digital design and manufacture has been the norm for years, product manufacturers look at similar developments in AEC and see only fragmented and overlapping processes and technologies. This makes it difficult to understand what construction professionals want downloadable Building Information Modelling (BIM) content to do.
Many product manufacturers are only just starting to contribute information to the industry in a BIM format, by providing intelligent, data-rich digital product objects. For most it is proving bewildering.
The demand side must help the supply side by providing guidance and feedback on how objects should work at different stages of design and construction. There are now a number of firms working with manufacturers to convert real life building components into downloadable BIM content for construction professionals to improve modelling productivity and embed vital information that assists downstream stages of the building process, from quantity take off, purchasing, installation and servicing.
Defining the object
BIM objects are the building blocks of a building but how objects perform, and the terminology used to describe them, varies between authoring tools so the following points can only be at a general level.
Objects are made up of three closely inter-related parts: geometry, data, and visualisation. Geometry describes the physical form of the object; data are the attributes of the object ranging from a simple fire rating through to complex parameters which dynamically change the geometry of the object; and visualisation, which determines how the object is to be displayed. Some ‘objects’ do not conform to this structure and, as an example, may only have a texture definition so that they can be placed onto system components or other objects, e.g. a fabric texture applied to a chair.
Objects can be divided into several types:
- Textures and finishes, which can be both generic and manufacturer specific and may be incorporated into other objects but may also be stand alone.
- Material descriptions and system components, which can be both generic and manufacturer specific
- Simplified objects for spaces and functional requirements
- Generic objects, which can be global or reflect local requirements
- Manufacturer specific objects, which reflect product logic and have detailed configuration options
Objects can be static, where there is no variation from the one size, one colour, etc. or they can be parametric, where parameters can drive the geometry, data and visualisation of the object. As with the differences in the way BIM tools handle objects so it is true that there are some file formats, like OBJ, 3D DWG and 3DS that can only handle static objects and IFC has only very limited support for parametric objects.
Parametric objects can be very clever in what they can do and how they can be driven. However, BIM authoring tools can hinder the potential benefits of an object-based solution unless add-on software is also written to realise the full potential of the downloaded components. A simple example of a useful object is where a door or window can be swung so that the minimum space requirements can be checked visually.
Parametric objects developed for manufacturers are usually configured to support the product structure and logic for various BIM tools, but the parameters must also support how the object will be used during the phases of development in construction.
Unlike mechanical CAD systems, which design in 3D and connect directly to CNC machines, BIM objects have to accommodate 3D and 2D. These objects need to perform in a 3D context but because of traditional requirements also have to provide correct 2D documentation showing plans, sections and elevations. From feasibility studies through to completion, varying levels of development are required to deliver both the correct visual representation for documentation purposes and ensure the relevant associated data is available for downstream use. This means delivering the right information for the right project stage.
Advanced BIM software uses data and graphics information in dialogue boxes in the object’s user interface to show illustrations, menus and graphics. These can be used to show graphs of acoustic performance and fire resistance, which can contribute to the user quickly understanding how the product should be configured. This ‘smartness’ can also extend to sub-components, which usually would not be modelled, but for quantification purposes could be calculated based upon attachment or placement patterns, number per area. Typical examples of sub-components would be fastners, adhesives and sealants.
Objects can carry any amount of data if the geometry has been programmed to produce a lean object. The data being carried needs to be fit for the intended purpose(s), i.e., what data is required for different project phases and what place holders are required for data that will be added during a phase. Much of the data required may not be carried but instead be referenced through hyperlinks in the object. Only one original version of an object and any linked data should exist on the Internet to avoid problems from an outdated source and also to minimise the cost of maintenance.
We can expect objects to continue to get smarter and to carry more data. Links to material and chemical databases and other information sources will provide new levels of analysis. Every national classification system will be available. Objects carrying their own constraints into rule based model checkers like Solibri.
There are endless possibilities and with smart cloud and web services users will be able to select how smart the object will be and what range of data will be available, for a particular design or construction phase.