Monday, February 11, 2013

IfcOpenShell 0.3.0 released!

After another (rather lengthy) period of testing we proudly announce the immediate availability of IfcOpenShell 0.3.0, the latest stable release of this open source toolkit for working with IFC files.

Meanwhile several interesting new features have already been developed in anticipation of the following release: Support for writing IFC files is especially something to look forward to given the powerful geometry back-end based on Open Cascade. Note that these features will not be available in the 0.3.0 release though.

Thanks go out to everybody for reporting bugs and contributing to this release. Naturally this includes everybody using IfcOpenShell and those being involved in the discussion and adoption of IFC in the AEC industry as well.

Changes since 0.3.0-rc3

Parsing and geometry
  • Potentially faster processing of files that can not be parsed sequentially, i.e. that require many random access operations throughout the file
  • Fixed a bug that caused IfcCircleHollowProfileDefs to be processed incorrectly
  • More robust processing of IfcCompositeCurves if no plane angle unit is provided in the file
  • More robust processing of IfcTrimmedCurves with tolerances on trimming by IfcCartesianPoint and, if possible, falling back to trimming by IfcParameterValue
  • Updated for Blender 2.65
  • Allow opening of non-latin filenames on Windows (other platforms already supported this)
  • Use positive vertex indices for Wavefront OBJ files, which is more widely supported in importing applications
  • Updated for Autodesk 3ds Max 2013
  • Allow opening of unicode filenames (only in 3ds Max 2013)
BIMserver IfcEngine
  • No longer throws an exception if a building element's geometry is requested for an element that has not been processed by the IfcOpenShell binary

The release can be downloaded from the website:
Enjoy! And remember that IfcOpenShell still needs your help!


  1. Wow great! I look forward to some good open BIM implementations. 2 questions:
    A: Will the future IfcOpenShell then make it possible to import->edit->re-export ifc models?
    B: Will it be possible to create and export bim/ifc geometry directly from Blender?

    Also thanks for doing this work! It is sorely needed and very much appreciated.

  2. Hi Ejnar,

    Thanks :) I think doing minor corrections and annotations from Blender is something IfcOpenShell in the long run definitely will support, but actually creating IFC geometry in Blender from scratch might be a different story. Blender is not that much oriented towards precision modelling. Even though some modifiers, like the extrusion and boolean modifier could be used to model in way that is close to the tools that BIM applications offer, on the other hand, the strict hierarchical notion of IfcBuildingStoreys for example is completely lacking in Blender, as well as different representations for a single object. Anyway, if you have some input or ideas they're always welcome.

    Kind regards,

  3. I see.
    Yet I am not very discouraged because I just read about the coming release of FreeCad. I ead you are talking to Yorik and it seems that FC is much more suited to work with the BIM modeling concept. And it seems there might be some nice integrations between Blender and FC.
    This is actually moving and I am very excited about where you are all headed.

  4. Hi again Thomas.

    I am still very busy but it seems I will have some spare time this summer and I would like to have a look at the BIM pipeline in open source software. I am an architect and everywhere this field moves to BIM programs. I really like that approach for the planning of the projects, but Revit or ArchiCAD do not cover my creative need for conceptual massing before the planning and the artisting rendering after the planning.
    I have some ideas I would like to work on and I would like to discuss but where is the best forum for discussing with you?

  5. Hi, welcome back Ejnar. Sounds good. It depends on your personal preference: you can reach me at or, preferably, if you want others to participate as well, open up a forum thread at . There also is a freenode irc channel #ifcopenshell, but I am not always around.

    Kind regards,

  6. Hello, first of all, I want to congratulate you, for the great work on making the ifcopenshell.
    But when I try to export an IFC of more than 100MB, it's exported to an OBJ of more than 600MB, that is enormous for my purpose, there's some solution to reduce that exported size?

    1. Hi AbraĆ£o,

      Thanks for your message.

      The size of the .obj file depends largely on the exact geometrical contents of the IFC file. The file sizes you mention do not seem outrages to me: 100 MB of IFC data if fairly large and OBJ is not an efficient format.

      There is currently no easy way to set the deflection (tolerance for curved surface approximation) that IfcOpenShell uses. If the file has many curved surfaces that would have been a good way to reduce the fidelity and file size of the conversion. Secondly, the conversion is inefficient, because geometry definitions in the IFC file, that are used multiple times for different instances, are not shared in the converted file. Both of these limitations will be addressed in an upcoming release of the new, more advanced, IfcConvert utility.

      Kind regards,

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