BIM is often presented as a multi-dimensional design methodology, in which a 3D model is enriched with information on scheduling (4D), cost control (5D), sustainability (6D), and so on. Each new dimension after the time axis does not stand for a physical dimension, but rather metaphorically for additional degrees of freedom that can be added to the model. This is remarkable, since the term dimension is used only partially in its actual sense. This can create the impression that the higher dimensions are downstream in the design process and can be viewed as "optional". However, costs are an essential indicator of whether a project will be pursued at all. Misguided optimization can happen to the detriment of operating costs, which has a negative impact on life cycle costs and possibly on the sustainability of the building. The higher "dimensions" such as cost and sustainability must therefore be considered early in the design process.
In practice, such considerations are - if at all – unfortunately often only considered at a late stage. The actually enormous work step in the early service phases 1 to 3, in which a three-dimensional building model is to be created from a requirements planning, does not require a separate mention in most popular displays of the BIM method. This is presumably due to the fact that the involved architects usually create initial three-dimensional models on the basis of intuitive considerations. The depth of depiction of technical facilities is often kept to a minimum, since technical access areas, in contrast to utility and traffic areas, have no representative value.
In order to break through the conflict of objectives between architectural, construction, and system engineering area and space requirements, DIN EN ISO 19650 proposes a so-called federation and information container division. What does this mean? Well, the aim is to essentially allow different task teams to work on parts of the information model simultaneously without introducing spatial or functional incompatibilities. The approach of the so-called "BIM according to ISO 19650" essentially aims to increase information security and to create a structural framework for collaboration - and this, if possible, before the individual teams delve into detailed design tasks. To this end, spatial boundaries are to be defined within which each task team should find the systems, components, or building elements for which it is responsible. ISO 19650 distinguishes between primary linear and spatially complex structures. Primary linear structures, such as shafts or pipeline corridors, can be represented by a dimensioned cross-section; more complex situations are ideally represented by a collection of interlocking obstructions. A pleasant side effect: In working practice, a permanent superimposition of different detail models is thus obsolete; for many coordination tasks, the exchange of lightweight information models is sufficient.
The design approach taken by the LINEAR software in early phases appropriately represents these recommendations in the discipline "pipeline corridor concept". It extends the basic ideas with intelligent information containers for the structural mapping of necessary spaces for different technical media and electrical systems. This simplifies the design and documentation of pipeline corridor cross-sections by using intuitive tools. The given information is also used to support the dimensioning of the necessary information containers and to simplify the transition to detailed design phases. This makes it possible to agree on space requirements at an early stage using lightweight models.
One of the main challenges in creating three-dimensional design models is that classical modeling techniques do not permit a flexible response to changes. If you work at a modeling level where the involved trades have already built at the component level, even the simplest changes will require time-consuming modifications. In the following, we would therefore like to outline an alternative approach that makes it possible to work together in early design phases towards a three-dimensional pre-concept design model that forms the basis for the subsequent process steps. The basic premises here are an iterative model development from coarse to fine and the end-to-end use of data across all development stages.