Model View Definition (MVD): key aspects of the IFC views and their use in BIM data exchange
In this post I’ll explain what a Model View Definition (MVD) is and how it enables effective IFC information exchange.
MVD (Model View Definition)
MVDs are defined by buildingSMART International as IFC schema subsets to describe data exchange for a specific use or workflow.
These filtered IFC views basically allow you to simplify the data exchange process and to avoid sharing useless or redundant information while following standardized procedures.
The following image shows the completeness of the IFC schema and how a specific MVD is able to streamline it according to the information useful for a specific scope.Clearly, the MVD is a filtered view that allows users to export specific packages of the model information to meet a particular use.
Let’s imagine that we have an entire building model, that is a digital twin complete with schematic information. We can simulate this model through a federation of models.
The different MVDs applied to the federated model will allow us to obtain:
- a structural model
- an architectural model
- a MEP model
The function of the MVD is to support the data exchange scenario and provide an optimal approach for software developer to implement IFC-based information.
Here is a list of the different MVDs that refer to different construction areas and to different IFC versions that you can check on the buildingSMART website:
|IFC SCHEMA||MVD||PUBLICATION STATUS|
|IFC 2X3||Coordination View||published|
|IFC 2X3||Space Boundary Addon View||published|
|IFC 2X3||Structural Analysis View||published|
|IFC 4||Reference View||published|
|IFC 4||Design Transfer View||published|
|IFC 4||Quantity Takeoff View||NOT published|
|IFC 4||Energy Analysis View||NOT published|
|IFC 4||Product Library View||NOT published|
|IFC 4||Construction Operations Building Information Exchange||NOT published|
Model view definition and software certification
Another function of the MVD is its use for the certification of software that can control certain processes.
In fact, buildingSMART grants a certification when a software can correctly manage the set of classes present in the IFC schema and which are included in a specific MVD.
Here is the page with all the software certified by BSI.
For each certified software on the BSI website, it is evident that the following aspects are showed:
- schema version (ex: IFC 2×3)
- MVD- exchange/requirement (ex. CV 2.0 arch)
- report link, with all the specifications of the tests performed for the certification. These datasheets can also be downloaded.
Model view definition: the IFC example ready for download
Let’s now take a closer look at a practical example to better understand MVD and what are its functions in an IFC file.
The file contains a federation of 3 models:
- Installation systems
You can view the different entities present in the IFC file with their properties. In this regard, just select the entity and read the relating values in the properties toolbox (on the right-hand side).
In addition, you can also recreate selection groups and selection filters that will both allow you to recall the object selections any time, hence making the file management simple and streamlined.
The selection groups are set of objects that you can choose directly from the 3D view and that you can name.
For example, you can create selection groups for:
- components installed on the same day;
- supplies from the same company;
- items that need maintenance;
The selection filters are object sets that are filtered according to certain characteristics they have in common, for example the kind of entity (eg. All the windows), geometry (dimensions), characteristics and properties, IFC file membership, etc.
In particular, it is necessary to specify :
- IFC file
Try usBIM.viewer+ and create filters or groups in the file that you have downloaded.