The concept of building information modelling (BIM) has received universal acceptance from the building services, structural engineering and architectural fraternity mainly due to its need for lean construction and also its cross-disciplinary usability. 3D BIM modeling has existed for a number of years now and the industry is aggressively adapting itself to embrace the new work flows of the BIM process; however, there is still a lack of clarity amongst the owners (the clients) as to what exactly they can achieve from these models, what they need to achieve and how they can make optimum use of this concept.
This article seeks to explore some beliefs related to the use of BIM and sheds light on when it should be used and to what extent. For the sake of clarity, it is important to know the difference between non-BIM 3D CAD models and a parametric BIM models.
3D CAD models are virtual representations of a facility that provide only visual details. Applications such as AutoCAD Architecture and AutoCAD MEP are used to create 3D CAD models that can be used for design, development, construction and pre-fabrication. On the other hand, BIM models are intelligent models embedded with parametric details that are extremely important for design, development, construction, pre-fabrication, assembly, analysing energy performance and facility management of the built environment. For BIM projects, the details can be effectively shared between different project stakeholders: facility owners, designers/architects, MEP (M&E) engineers, fabricators, consultants and contractors. Revit Architecture and Revit MEP are applications used for BIM modelling whilst Navisworks is employed to detect clashes between different system models.
One of the most crucial aspects that helps decide whether BIM is actually required or not is gaining an in-depth understanding of the model's purpose. More often than not, there is so much difference between client's 'stated' needs and his/her 'real' needs. In a lot of cases, clients state that they require a BIM model but actually what they require is a smart clash-free 3D model which can be used to extract respective construction drawings. In such scenarios, AutoCAD MEP or AutoCAD Architecture could easily be used to provide a 3D model that meets this need. Alternatively, a BIM software tool could be used to provide a 3D model without providing additional elements such as data rich 'information'.
In other cases, a BIM model may actually be the basis to plan, design, construct, and manage a particular facility. These scenarios require multidisciplinary project stakeholders to access the BIM model at different stages in the project life cycle. As a result, the most important factor that dictates the success of any project employing BIM is the richness of 'information' embedded into the models.
So, depending on the project's scope, a full-fledged BIM model may contain valuable information, such as dimensions of building elements, quantity take-off data, material requirements, time scheduling, costing, prefabrication data, activity simulation, and energy performance. Other important factors that contribute to success of BIM include the data-sharing and interoperability standards to allow smooth multidisciplinary collaboration between key disciplines.
Irrespective of whether the client actually requires BIM or non-BIM CAD model, the BIM wave that has spread across the AEC industry has forced the agenda to adopt a more progressive approach to planning, designing and coordinating models and drawings.
The industry continues to transition from non-BIM 2D approaches to collaborative BIM work flows and 3D CAD work flows and even that is a huge shift for the industry. This change is more often than not influenced by the demand side i.e. the clients.
