This is an initiative to expose the functionality of IfcOpenShell for parsing and writing IFC files to a Python interface. The creation of a topological representation for building elements using Open Cascade is also wrapped by returning a string serialization of the Open Cascade TopoDS_Shape. Using SWIG a wrapper is obtained for a C++ Class which evaluates its Express attribute names and indices at runtime. The functions created by the SWIG wrapper closely resemble the C++ structure. The idea is to create an additional wrapper around these function in Python that is more idiomatic to Python.

>>> import IfcImport

>>> f = IfcImport.open(filename)

>>> f.by_type("ifcwall")

[#170=IfcWallStandardCase('0lJANQLbCEHPkU1Xq9w_bk',#13,'Wand-001',$,$,#167,#240,'2F4CA5DA-5653-0E45-9B-9E-061D09EBE96E'),

#288=IfcWallStandardCase('1sFBHOg98nGQTuD1XjjAKK',#13,'Wand-002',$,$,#285,#358,'763CB458-A892-3141-A7-78-34186DB4A514')]

>>> brep_data = IfcImport.create_shape(wall)

>>> wall.get_argument_count()

>>> wall.get_argument('GlobalId')

'0lJANQLbCEHPkU1Xq9w_bk'

>>> wall.get_argument_index('Name')

2

>>> wall.set_argument(2,"John")

>>> wall.get_argument('Name')

'John'

>>> wall.get_argument_index("foo")

File "IfcImport.py", line 112, in get_argument_index

def get_argument_index(self, *args): return _IfcImport.Entity_get_argument_index(self, *args)

RuntimeError: Argument foo not found on IfcRoot

>>> wall.set_argument(5,"Hi")

File "IfcImport.py", line 114, in set_argument

def set_argument(self, *args): return _IfcImport.Entity_set_argument(self, *args)

RuntimeError: STRING is not a valid type for 'ObjectPlacement'

>>> e = IfcImport.Entity("IfcJohn")

Traceback (most recent call last):

File "<stdin>", line 1, in <module>

File "IfcImport.py", line 105, in __init__

this = _IfcImport.new_Entity(*args)

RuntimeError: Unable to find find keyword in schema

>>> pnt = IfcImport.Entity("ifccartesianpoint")

[60478 refs]

>>> pnt.set_argument(0,IfcImport.Doubles([0,0,0]))

[60486 refs]

>>> pnt

=IfcCartesianPoint((0,0,0))

>>> f.add(pnt)

**TODO**: By creating an additional wrapper in Python around these methods some syntactic sugar can be added so one is able to say the following instead:

d = IfcDocument()

my_wall = d.createIfcWallStandardCase("1$gyu8123...",Representation=my_repr)

With a document specifying a 'catch-all' function that creates the ifc entity based on the method being called, perhaps like so:

class IfcDocument:

def create_entity(self,type,*args,**kwargs):

e = new IfcEntity(type)

# set all attributes in args and kwargs

self.add(e)

return e

def __getattr__(self,attr):

if attr[0:5] == 'create': return functools.partial(self.create_entity,attr[5:])

...

Ubuntu Notes

The following sequence of commands has been tested successfully on Ubuntu 14.04.

OCE installation. This step worked OK with cmake 2.8.12.2, gcc 4.8.2, g++ 4.8.2. Also, it might take up to an hour to complete.

apt-get install git cmake gcc g++ libftgl-dev libtbb2 libtbb-dev libboost-all-dev

cd /

mkdir git && cd git

git clone https://github.com/tpaviot/oce.git

mkdir oceBuild && cd oceBuild

cmake ../oce

make -j4

sudo make install

IfcOpenShell installation. This step worked OK with cmake 2.8.12.2, gcc 4.8.2, g++ 4.8.2.

apt-get install swig

cd /git/

git clone https://github.com/aothms/IfcOpenShell.git

cd IfcOpenShell/cmake

mkdir build && cd build

cmake ../

make -j4

Once done, IfcConvert is to be found in the build folder.