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VW and BIM, Interoperability tests using IFC

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I recently did some performance testing of Vectorworks Architect/Designer 2009 SP4, specifically focusing on the IFC export functionality. As I have mentioned before, the IFC file format is THE internationally recognized data transport vehicle for BIM.

Many of you have had questions about VW's IFC capabilities and how that relates to sharing information with other apps. Well, today I'm providing snapshots of how the testing went.

The building model used is the Modern Home Prototype found on the BIM in Practice Projects page < http://www.nemetschek.net/bim/projects.php >. It was recently added and is the culmination of work done through the VW2009 development cycle. The model makes extensive use of VW plug-in objects to create a "virtual construction" model. There are a great deal of Framing Members of all types and configurations, floor slabs, even repurposed as ceiling plans and floor finishes, among many of the other standard VW objects.

The IFC export is based on the IFC2x3 TC1 specification and is considered a "Coordination View", essentially meaning that anything and everything that can be modelled as an anology to a real world object is included.

While not exhaustive, it is pretty extensive.

The following screenshots are the result of importing the IFC file, created by VW, into the respective applications.

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Batch 1:

AutoCAD Architecture 2010 and Revit Architecture 2010

AutoCAD Architecture 2010 results were pretty good. Many objects were either translated into native application objects, or were left as IFCProxy objects with correct geometry and data still attached. The geometry integrity, for the most part, was excellent.

Revit Architecture 2010 results were OK. Revit seemed to have issues with walls that had "non-flat" or "peaked" tops. The location of some objects (e.g. walls) were shifted in the Z-axis direction, in many cases. Most objects were translated into native app objects and held onto the IFC data.

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Batch 2:

Autodesk NavisWorks Review 2010 and Solibri Model Checker v5

NavisWorks and Solibri are the leaders in BIM model viewing and coordination. We use Solibri to do our primary sanity checking as it is a neutral third-party app used by many governments internationally, as a BIM review tool.

Both performed very well with Solibri edging NavisWorks in terms of geometric fidelity. Navisworks had a few issues with certain wall configurations.

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Batch #3

ArchiCAD 12 and Bentley Architecture V8i

ArchiCAD 12 did pretty well, but missed the site altogether and had many problems creating the correct wall openings for windows. All objects were translated to native objects, but a lot of individual custom .gsm objects were created for the doors, windows, and other objects. That is the nature of the GDL beast.

Bentley - Strange texture mapping aside (IFC doesn't really support colors OR textures, the apps do the mapping themselves), Bentley Architecture V8i had the highest geometry and data fidelity of all the apps tested.

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Batch #4 (final):

IfcStoreyView and DDS-CAD Viewer

IfcStoreyView is an application being developed by the Forschungszentrum Karlsruhe Institute for Applied Computer Science (Germany). It is an open source IFC data viewer. It is a very robust and fault tolerant application that we also like to use, mainly to check our results against Solibri. In this case there were a few geometry issues.

DDS-CAD is a well known European product that promotes IFC capability extensively. I am always on the lookout for "IFC-compliant" apps to test against. It gives us a good gauge to both our development quality and progress and that of the general market. I included it in this case to see that sometimes the same set of data can be viewed as unsuccessfully as other are able to successfully.

IFC is an open standard. And it is also a standard that is very flexible in the way it specifies the creation and interpretation of geometry. Because of that, some applications "cover all the bases" and can read data that may be encoded in any of a variety of ways. Other apps can handle only a handful of cases. What is important, is to act in the best interest of the community and continually test and report results, file bugs and improve functionality among all BIM products to encourage true interoperability.

Edited by Jeffrey W Ouellette
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  • 2 months later...
Thank you, Kool Aid.

Judging from Jeffrey's test it even performed better.

You're welcome. Please allow me to elaborate: Solibri Model Checker is another product, the (expensive) current leader as comes to checking anything in IFC. The Viewer must use the same parser, so whatever looks good in the Viewer, will look good in the Checker. If your collaborator's software breaks a model that is fine in Solibri, that is (in theory at least) their problem, not yours.

In the tests I had an innocent bystander (an Associate Professor) to do in June with IFC-data from a beta version of VW 2010, other programs had various problems, but Solibri interpreted things mainly correctly. Now, my focus was entirely on my own objects and I have no idea whether the misbehaviour was related NNA's objects or mine.

The next best results, after Solibri, overall came from Autodesk's NavisWorks.

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