Building Information Modelling
Building information modelling is the Practice of building designs in 3D modelling software using BIM objects. It replaces the need for 2D CAD drawings and paper based draughting. Gaining widespread use after government mandate and increasing commercial sector interest.
Building designs can be built at different BIM levels called LOD -level of detail – denoting the amount of detail and data associated to the design. LOD 100 is effectively generic placeholder with some dimensional data. LOD 500 is the as built highly detailed level of data. Most BIM objects used in project designs beyond initial outlines use LOD200 or LOD300.
BIM models (project designs) have a graphical 3D geometry representation to allow stakeholders to ‘see’ the project design and the BIM objects that comprise it. This is now often done using virtual reality technology. The objects also have a properties table attached to them also called parameters table. This data is what ensures the object will work in the design. Such data includes dimensions, materials and performance. It is usual to include manufacturer details, maintenance regimes and other detail that would assist a building manager in running the building once constructed.
The BIM objects usually have 3D geometry which can be fixed or parametric. Fixed object is just that – fixed at a certain size and with fixed performance data. A parametric model allows the BIM designer to adjust some data within an object to flex it within the design. An example would be a door that has a nominal height, width and depth but which could be flexed to a greater or lesser size within limits set by the manufacturer that are embedded in the properties table.