BIM Wiki

One of the big fears surrounding BIM is that there is a loss of control. “How can we all possibly work on a single model?” “How do we control who does what, when?” These fears are based on a lot of misunderstandings. BIM is actually a very structured way of working. It’s not just about collaboration and sharing. It’s about defining specific protocols and workflows. openBIM standards, in particular, give us very strict controls for data exchange. In the openBIM workflow there is no single central model that everyone can access and modify as they like. Every project participant has their own model, of which they are the sole author. These models, or copies of them, are then exchanged at agreed intervals. So, we can divide the BIM process into two realms: Firstly, we have the native authoring environment where models are created and edited (this is the private domain of each discipline). Secondly, we have the collaborative environment where IFC copies of these models are viewed and coordinated. In this setup, no-one can access or change the model content of another discipline. There are clear lines of communication. If changes to a model are required, these are tracked and reported on. This was discussed in a previous video. More than this, in an openBIM workflow, we can predefine exactly what information needs to be transferred when and by whom. This is achieved with Model View Definitions, or MVDs. An MVD is essentially a filtered view of the IFC. It allows users to export specific packages of model information to meet a particular use. For example, if an architect needs to deliver their model for energy analysis, they don’t just do a data dump of the entire model. They select the predefined IFC export called Energy Analysis MVD. This exports only the information that is relevant (the building envelop, spaces and u-values for external walls). Similarly for cost estimation, you would choose the QTO Model View Definition, or for structural analysis, you would export the Structural Analysis view. The Model View Definition is a really powerful tool in the openBIM workflow. It helps enforce clear and structured ways of working. Further Resources: www.buildingsmart-tech.org/specifications/ifc-view-definition

1 BIM BIM, building information modeling, refers to the use of digital models to support the design, construction and operation of buildings. 2 openBIM openBIM describes a method of BIM based on open exchange standards. These support communication between project teams using different software tools. For example, to transfer a model from Autodesk Revit to Allplan. 3 IFC IFC is an exchange format that is at the heart of openBIM. If an architect wants to share his model, he has to make an IFC export from his modeling software, which he can then pass on to other planning partners. 4 LOD – Level of Detail or Development Level of Detail or Development describes the geometric detail of a BIM object at different phases. It is a BIM convention that replaces tradtional conventions of  drawing scale. Instead of 1: 100- 1:10, we talk about LOD100-LOD500. 5 LOI – Level of Information The Level of Information, or LOI for short, describes the information content of a BIM object at a specific time in the project. LOI refers to the properties of an object; for example, dimensions, material specification, insulation, or the costs of the building element.

We know that BIM is a digital method for planning, construction and operation. But what really sets it apart from 2D or even 3D? 2D planning in CAD is simply a digital version of drawing on a drawing board. We may be able to erase elements more quickly or copy them several times, but the processes are the same. 3D models add volume and surfaces to 2D plans, however, ultimately this is still a drafting process. With BIM, we work with individual building elements that are not only presented in 3D, but also contain information. For example, an object may be tagged with the floor and room number in which it is located. It can also contain information about material specification or cost. Plans, sections and schedules can be produced directly out of the model. In fact, plans are just an extracted view of the model data. A change in the view is immediately updated in all other representations. This helps in managing changes and is one of the first and simplest values of BIM. Furthermore, you can browse and filter the BIM models so that you can view specific information for a specific purpose. An example could be to display all load-bearing walls, or simply to show what has changed from the last planning state to the current one. BIM also allows for analysis and simulation of model information. For example, for static calculations, energy simulations or light and shadow studies. All these possibilities increase efficiency and help us to evaluate and compare design options. BIM does not replace the expertise of designers, but helps eliminate menial, repetitive work. This gives us more time to make the best decisions.

At the moment it seems there is nothing BIM can not do! It can be hard to distinguish the facts from the myths. In this video we address some of the most common BIM claims.   BIM is only for big projects No, that is not correct. Of course, the bigger the project, the more involved you are; the coordination of trades becomes more complex and production of plans is more time intensive. However, this is largely a question of scale. We are essentially dealing with the same problems, regardless of the project size. There is a value in digital ways of working, even on small projects. As a company, ask yourself, where are bottlenecks, difficulties, and then see if there are any ways to improve them.   BIM completely changes the way we plan today Yes and no. BIM will change the way, but perhaps not the way you expect it to. BIM does not mean throwing all our existing processes out of the window. Actually, it’s just the opposite. BIM is about creating and improving structures based on the experience we have. The project roles and responsibilities remain identical, but with more communication, clarity and understanding. It’s more helpful to talk about an improvement than to work from a whole new way of working.   With BIM we all work on a single model That’s not true. The idea that all planners can work on a single model is a myth. BIM is not a central model, rather a collection of several different models or databases linked together. The advantage is that every stakeholder remains the owner his model and discipline. Likewise, only he has the opportunity to make alterations. This preserves the traditional ways of communication, the roles and responsibilities.   With BIM I have to change the complete IT and CAD environment That depends on your current environment. Most planning companies already have powerful computers and may have BIM compatible software. The only thing missing is to implement BIM processes. In this case, BIM is more of a business process and investment in employee education than in a completely new IT environment.   BIM works only in collaboration with other planners Not quite. BIG BIM needs the collaboration of planners to share models and information. But also to plan ahead for the future of a project. However, it has to be said that such projects require a certain amount of experience and competence. We therefore recommend starting with BIM as an internal may of working, to improve your own processes. This is called little bim. Once you implemented these processes, then a BIG BIM project is just a small step away.