Another Clash Detection Solution?

Although we already are committed to NavisWorks for Clash Detection, we have been doing a bit of research to see what else is available. One of those potential solutions is provided by Solibri: Model Checker.
Model Checker has been featured in several articles as a clash detection solution: AIArchitect, AECCafe, and AECbytes to name a few. However, when I looked into it, it didn't seem like much of a solution. From the information on their website, I inferred that it only imports IFC files. To me, this seems like a problem; I thought that IFCs weren't fully developed for most disciplines (especially those crucial for clash detection).

So I contacted Solibri, asking:
From what I've read about your software, it only imports IFC files. Is this true?
  • If so, can you send me some information on IFCs; it is my understanding that they are only developed for architecture and structure. (Is that the case?)
  • If not, what other file formats can be imported into Solibri?
Heikki Kulusjärvi, Managing Director of Solibri, responded:
Solibri Model Checker reads IFC files. "Only" is a word I would not use as IFC's are exported from all major BIM authoring tools like ADT, Revit Bentley Architechture, ArchiCAD, Tekla Structures and many more. There are also building services products producing IFC's.
In addition to IFC's SMC has a two-way seamless communication with ArchiCAD.

That didn't really answer my question. So we did a test. We exported 3 Revit models (an architectural, a structural and a HVAC model) to IFC format from Revit. We exported those same models to NWC format from Revit. We opened the two composite models in NavisWorks. When we click on a specific water heater in the NWC model, the properties read "Water Heater - 2". When we clicked on the same water heater in the IFC model, the properties read "Solid Mass".

The intelligence of our model wasn't exported in the IFC format. My conclusion: Solibri isn't really an effective clash detection solution.

Or does anyone know if I am mistaken about IFCs?

2 comments:

James Van said...

Laura - As another test, you might want to export your Revit model to IFC, then import it back into a blank Revit file. Check your objects (particularly the water heater) to see if it's Revit's IFC export or Solibri's IFC import that is faulty.

Heikki said...

Well, as you are committed to use Navisworks it’s natural to compare other tools to that.

If you want to find out a bit more what Solibri Model Checker (SMC) is you will notice that it’s doing much more than just the clash detection. SMC is using rules to analyze the quality of BIM files. It checks that spaces are modelled correctly compared to surrounding walls (you get the sf right), it has functionality to analyze egress routes, rules to ensure that information is usable for QTY-Take-off and cost estimation purposes.
We have also built specific rules to our customers:
- US General Services Administration (GSA): check that GSA BIM guide requirements www.gsa.gov/bim (Spatial Program Validation) are fulfilled,
- Statsbygg Norway (GSA equivalent), Skanska Finland: Accessibility analysis based on ISO standard (ADA)
- and many more

Yes, all in IFC format “only”.

You raised a good question about clash detection. What is your “Water Heater - 2” really?

I assume that in Revit HVAC solution this component has intelligence in a way that it has connection points to piping system and electrical system. What is the information that you really have in Navisworks? Does the component now know that it’s part of the heating system, does it know where the connection points are? It sounds to me that all “intelligence” there is was written by the user: “Water Heater -2”. What if you typed it to be a “Column -2”? Would it be a column now? The only thing Solibri Model Checker and also Navisworks really know is that it is a “Solid mass” geometrical component. If you connect a pipe in it will you have a clash or a connection?

The idea of IFC is to define the behaviour of these components so that the receiving system “understands” what the component is and can reason with it. In your case you used a HVAC system that does not currently support exporting IFC’s this way. Revit is certified to work with Architectural and Structural components but not (at this point) with Building Services components.
HVAC systems supporting IFC’s are e.g. DDS http://www.dds-cad.co.uk/, MagiCAD http://www.progman.fi/ both now IFC certified.

Please check the IFC file you wrote from Revit. It’s a text file and you can use a search function. Search for “Water heater -2” if the information is there then this could be used in Solibri Model Checker as well. With out this information you can still check clash detection with this “object” and others but the SMC rules would not automatically recognize this as part of the heating system.

I hope this clarifies.