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IfcOpenShell is an open source (LGPL) software library for working with the Industry Foundation Classes (IFC) file format. Extensive geometric support is implemented for the IFC releases IFC2x3 TC1 and IFC4 Add2 TC1. Support for parsing is provided for IFC4x1, IFC4x2, and the IFC4x3 release candidates. Extending with support for arbitrary IFC schemas is possible at compile-time when using C++ and at run-time when using Python.

For more information, see

Build Status

Financial Contributors


  • Git
  • CMake (3.1.3 or newer)
  • Windows: Visual Studio 2008 to 2019 (2022 not yet supported by dependency CMake) with C++ toolset (or Visual C++ Build Tools) or MSYS2 + MinGW
  • *nix: GCC 4.7 or newer, or Clang (any version)


  • Boost
  • Open Cascade - optional, but required for building IfcGeom (official, "OCCT", or community edition, "OCE")
    For converting IFC representation items into BRep solids and tesselated meshes
  • OpenCOLLADA - optional
    For IfcConvert to be able to write tessellated Collada (.dae) files
  • SWIG and Python - optional
    For building the IfcOpenShell Python interface and the Blender add-on
  • 3ds Max SDK - optional
    For building the 3ds Max plug-in. All recent versions of 3ds Max (2014 and newer) are 64-bit only, so a 64-bit installation is assumed.

Building IfcOpenShell

Note 1: The path where the source code is cloned to can contain spaces but non-ASCII characters are very likely to cause problems with the build.

Note 2: If you had not used git clone --recursive, update the submodules by running git submodule init & git submodule update.

Note 3: Be careful with special characters is the path when using the nix or win build scripts, because the OpenCASCADE build will fail on paths containing ++ and likely other situations.

Compiling on Windows

The preferred way to fetch and build this project's dependencies is to use the build scripts in win/ folder. See win/ for more information.

Using Visual Studio

Instructions in a nutshell (assuming Visual Studio 2015 x64 environment variables set):

> cd IfcOpenShell\win
> build-deps.cmd
> run-cmake.bat

NB: build-deps.cmd need to be ran from the directory containing it, i.e. the ./win folder.

You can now open and build the solution file in Visual Studio:

> ..\build-vs2015-x64\IfcOpenShell.sln

As the scripts default to using the RelWithDebInfo configuration, and a freshly created solution by CMake defaults to Debug, make sure to switch the used build configuration. Build the INSTALL project (right-click -> Project Only) to deploy the headers and binaries into a single location if wanted/needed.

Alternatively, one can use the utility batch file(s) to build and install the project easily from the command-line (installing a project will build it also, if required):

> install-ifcopenshell.bat

Using MSYS2 + MinGW

Start the MSYS2 Shell and then:

$ cd IfcOpenShell/win
$ ./
$ ./
$ ./

Using Bash on Ubuntu on Windows

Start Bash on Ubuntu on Windows and follow the instructions below. Compiling on Ubuntu 14.04.4 LTS using GCC 4.8.4 or Clang 3.5 has been confirmed to work.

Compiling on *nix

The following instructions are for Ubuntu, modify as required for other operating systems. nix/ script can be experimented with and studied for pointers for other operating systems, but note that this script is not currently meant to be used for a typical IfcOpenShell workspace setup.

Note 1: It is recommeded to use OCCT for IfcOpenShell. You could use OCE as well, but sometimes it may lag behind OCCT and therefore not compile with the latest IfcOpenShell.

Note 2: where make -j is written, add a number roughly equal to the amount of CPU cores + 1.

1) Install most of the prerequisites and dependencies:

$ sudo apt-get install git cmake gcc g++ libboost-all-dev libcgal-dev

2a) Either use an OCCT package from your operating system's software repository

$ sudo apt-get install libocct-data-exchange-dev libocct-draw-dev libocct-foundation-dev libocct-modeling-algorithms-dev libocct-modeling-data-dev libocct-ocaf-dev libocct-visualization-dev

2b) or, if OCCT is not available or the latest code is wanted, obtain and compile OCCT from

2c) or, if you'd like to try using OCE, use the package from your operating system's software repository

$ sudo apt-get install liboce-foundation-dev liboce-modeling-dev liboce-ocaf-dev liboce-visualization-dev liboce-ocaf-lite-dev

2d) or if OCE is not available, or the latest code is wanted, compile OCE yourself (note that the build takes a long time)

$ sudo apt-get install libftgl-dev libtbb2 libtbb-dev libgl1-mesa-dev libfreetype6-dev
$ git clone
$ cd oce
$ mkdir build && cd build
$ cmake ..
$ make -j
$ sudo make install

3) For building IfcConvert with COLLADA (.dae) support (on by default), OpenCOLLADA is needed:

$ sudo apt-get install libpcre3-dev libxml2-dev
$ git clone
$ cd OpenCOLLADA
Using a known good revision, but HEAD should work too:
$ git checkout 064a60b65c2c31b94f013820856bc84fb1937cc6
$ mkdir build && cd build
$ cmake ..
$ make -j
$ sudo make install

4) For building the IfcPython wrapper (on by default), SWIG and Python development are needed, if not already available:

$ sudo apt-get install python-all-dev swig

5) To build IfcOpenShell please take the following steps. Alternatively use environment variables for setting the dependencies' paths. OCC_INCLUDE_DIR might be needed to set also. OPENCOLLADA_INCLUDE_DIR and OPENCOLLADA_LIBRARY_DIR (and potentially PCRE_LIBRARY_DIR) are needed if building with COLLADA support. (-DCOLLADA_SUPPORT=0 disables it).

$ cd /path/to/IfcOpenShell
$ mkdir build && cd build
$ cmake ../cmake -DOCC_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu/ \
      -DOPENCOLLADA_INCLUDE_DIR="/usr/local/include/opencollada" \
      -DOPENCOLLADA_LIBRARY_DIR="/usr/local/lib/opencollada"  \
      -DPCRE_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu/ \
      -DCGAL_INCLUDE_DIR=/usr/include \
      -DGMP_INCLUDE_DIR=/usr/include \
      -DMPFR_INCLUDE_DIR=/usr/include \
      -DGMP_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu \
      -DMPFR_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu \
$ make -j

If all worked out correctly you can now use IfcOpenShell. See the examples below.

6) Install the project if wanted:

$ sudo make install

Installing on MacOS Using Homebrew

1) Install all dependencies using Homebrew

$ brew install boost swig cmake ftgl cgal gmp libaec opencascade

2) Clone the git repo and its submodules

$ git clone --recurse-submodules 

3) Build IfcOpenShell with flags for Homebrew dependencies (/usr/local/)

$ cd /path/to/IfcOpenShell
$ mkdir build && cd build
$ cmake ../cmake -DOCC_LIBRARY_DIR=/usr/local/lib/ \
      -DOCC_INCLUDE_DIR=/usr/local/include/opencascade/ \
      -DCGAL_INCLUDE_DIR=/usr/local/include/ \
      -DGMP_LIBRARY_DIR=/usr/local/lib/ \
$ make -j -lboost_options

Note: Make sure to compile using XCode, rather than a brew installed C/C++ compiler.

Installing IfcOpenShell with Conda

Another option for building and installing IfcOpenShell is to use the popular Anaconda Python Distribution. The requirements are spread across a number of channels. You can add these channels to your configuration, or specify them all on the command line:

$ conda install -c conda-forge -c oce -c dlr-sc -c ifcopenshell ifcopenshell

Usage examples

Invoking IfcConvert from the command line

$ wget -O\?id=4DsTgHFQAcOXzFetxbpRCECPbbfUqpgo
$ unzip
$ ./IfcConvert Duplex_A_20110907_optimized.ifc
$ less Duplex_A_20110907_optimized.obj

Using the IfcOpenShell Python interface

$ wget -O\?id=4DsTgHFQAcOXzFetxbpRCECPbbfUqpgo
$ unzip
$ python
>>> import ifcopenshell
>>> f ="Duplex_A_20110907_optimized.ifc")
>>> # Accessing entity instances by type:
>>> f.by_type("ifcwall")[:2]
[#91=IfcWallStandardCase('2O2Fr$t4X7Zf8NOew3FL9r',#1,'Basic Wall:Interior - Partition (92mm Stud):144586',$,'Basic Wall:Interior - Partition (92mm Stud):128360',#5198,#18806,'144586'), #92=IfcWallStandardCase('2O2Fr$t4X7Zf8NOew3FLIE',#1,'Basic Wall:Interior - Partition (92mm Stud):143921',$,'Basic Wall:Interior - Partition (92mm Stud):128360',#5206,#18805,'143921')]
>>> wall = _[0]
>>> len(wall) # number of EXPRESS attributes
>>> # Accessing EXPRESS attributes by name:
>>> wall.GlobalId 
>>> wall.Name = "My wall"
>>> wall.NonExistingAttr
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".\", line 14, in __getattr__
    except: raise AttributeError("entity instance of type '%s' has no attribute'%s'"%(self.wrapped_data.is_a(), name)) from None
AttributeError: entity instance of type 'IfcWallStandardCase' has no attribute 'NonExistingAttr'
>>> wall.GlobalId = 3
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".\", line 26, in __setattr__
    self[self.wrapped_data.get_argument_index(key)] = value
  File ".\", line 30, in __setitem__
    self.wrapped_data.set_argument(idx, entity_instance.map_value(value))
  File ".\", line 118, in <lambda>
    set_argument = lambda self,x,y: self._set_argument(x) if y is None else self
  File ".\", line 114, in _set_argument
    def _set_argument(self, *args): return _ifc_wrapper.entity_instance__set_argument(self, *args)
RuntimeError: INT is not a valid type for 'GlobalId'
>>> # Creating new entity instances
>>> f.createIfcCartesianPoint(Coordinates=(1.0,1.5,2.0))
>>> # Working with GlobalId attributes:
>>> import uuid
>>> ifcopenshell.guid.compress(uuid.uuid1().hex)
>>> new_guid = _
>>> owner_hist = f.by_type("IfcOwnerHistory")[0]
>>> new_wall = f.createIfcWallStandardCase(new_guid, owner_hist, None, None, Tag='my_tag')
>>> new_wall.ObjectType = ''
>>> new_wall.ObjectPlacement = new_wall.Representation = None
>>> # Accessing entity instances by instance id or GlobalId:
>>> f[92]
#92=IfcWallStandardCase('2O2Fr$t4X7Zf8NOew3FLIE',#1,'Basic Wall:Interior - Partition (92mm Stud):143921',$,'Basic Wall:Interior - Partition (92mm Stud):128360',#5206,#18805,'143921')
>>> f['2O2Fr$t4X7Zf8NOew3FLIE']
#92=IfcWallStandardCase('2O2Fr$t4X7Zf8NOew3FLIE',#1,'Basic Wall:Interior - Partition (92mm Stud):143921',$,'Basic Wall:Interior - Partition (92mm Stud):128360',#5206,#18805,'143921')
>>> # Writing IFC-SPF files to disk:
>>> f.write("out.ifc")

Extra tools

Also available are a series of utilities that are based on or related to IfcOpenShell.

Those marked with an asterisk are part of IfcOpenShell.

Name License
bcf LGPL-3.0-or-later
blenderbim GPL-3.0-or-later
bsdd LGPL-3.0-or-later
ifc2ca LGPL-3.0-or-later
ifc4d LGPL-3.0-or-later
ifc5d LGPL-3.0-or-later
ifcbimtester LGPL-3.0-or-later
ifcblender LGPL-3.0-or-later*
ifccityjson LGPL-3.0-or-later
ifcclash LGPL-3.0-or-later
ifccobie LGPL-3.0-or-later
ifcconvert LGPL-3.0-or-later*
ifccsv LGPL-3.0-or-later
ifcdiff LGPL-3.0-or-later
ifcfm LGPL-3.0-or-later
ifcgeom LGPL-3.0-or-later*
ifcgeom_schema_agnostic LGPL-3.0-or-later*
ifcgeomserver LGPL-3.0-or-later*
ifcjni LGPL-3.0-or-later*
ifcmax LGPL-3.0-or-later*
ifcopenshell-python LGPL-3.0-or-later*
ifcparse LGPL-3.0-or-later*
ifcpatch LGPL-3.0-or-later
ifcsverchok GPL-3.0-or-later
ifcwrap LGPL-3.0-or-later*
qtviewer LGPL-3.0-or-later*
serializers LGPL-3.0-or-later*