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.