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REED SMARTBIM LIBRARY


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DWorks, this is what we mean by IFC not being "parametric". You have an expectation of IFC that is just not part of the protocol, at least as the schema currently stands. IFC is about sharing and referencing data-rich 3D building models, not about file exchange from one native format into another.

That's no excuse for the bad import VW does. When there is a wall in the ifc document, VW should read it like a wall. So for example, I draw a wall in Revit, export to IFC where it becomes a ifcWall, import it in Vectorworks where it becomes a (Vectorworks-) wall.

If ifc is about sharing data-rich 3D building models, then make sure these data fields are in the vw objects so you can translate these.

I don't want to import for nothing! IFC doens't need to be parametric, the programs that import/export it should import/export to/from parametric objects. So get away from the Create IFC command. Just build VW so that all building objects are IFC (have the needed fields, ....) and export/import them correctly!

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:) I like how you immediately assume I was talking about you. Chris, I have a huge respect for engineering (the best architects are also engineers), but, seriously, it really doesn't help your cause to just spill your brains out over your keyboard each time you write something.

If you used some conventional grammar etc. it would take less effort to read your posts.

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  • Vectorworks, Inc Employee

Petri, I don't know that I'd call IFC "geometry-poor." It really just doesn't support parameters. Parametric support is in fact being discussed for a future version of IFC. It's a two edged sword. What do you want: simpler geometry but parameters in a "dumbed down" version that all BIM applications can agree on, or exact geometry and data but no parameters? Each alternative has its advantages. I think there are very good and valuable workflows to be had with IFC-as-it-is.

BIM is one of those "intuitively obvious" topics that people "just get":

"of course! virtually build a building on my computer in 3D!"

...but when you really look at the workflows, exchanging of parametric (natively-editable) models creates more problems than it solves (in my opinion). It's possible to deliver an IFC model as an "instrument of service" without forcing the recipient into a strict intellectual-property-licensing scheme. I consider this a strength and not a weakness.

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DWorks, this is what we mean by IFC not being "parametric". You have an expectation of IFC that is just not part of the protocol, at least as the schema currently stands. IFC is about sharing and referencing data-rich 3D building models, not about file exchange from one native format into another.

That's no excuse for the bad import VW does. When there is a wall in the ifc document, VW should read it like a wall. So for example, I draw a wall in Revit, export to IFC where it becomes a ifcWall, import it in Vectorworks where it becomes a (Vectorworks-) wall.

It is not an excuse: since the IFC specification does not have a common definition of a wall, there is no way for VW to import "better". No program does: not Revit, not ArchiCAD, not Bentley.

(ii) Peruse the resulting file with a text editor. The geometric description of eg. a wall is a set of 3D triangles. Here is a wall with one opening:

I think you have misunderstood me. IFC doesn't need parameters. It has data fields and geometry. VW does the same at the base of each object. But they put an extra layer that you can call the parameter layer so that the users can easily change the object. So VW just need to translate the geometry in to parameters for their own objects.

For example: you have a wall. A wall have parameters like height etc... But in the end, it's just data and geometry. IFC can contain those data and geometry, so it's up to VW to say, hey, that geometry results in a wall of us with x for our height parameter.

And I know that in this way, every program needs to have the same parameters for their objects to have a good translation, and I think that's just the problem. A wall in VW can't have a changing section, while it does in other programs. And it's just these missing abilities in each program that makes it hard to define the IFC standard.

So the team behind IFC should say: These are the data and geometry you need to work with! and force the programs to adapt their software to use the same parameters. (I know, perfect word... )

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