Extra python modules

This page lists several additional python modules or other pieces of software that can be downloaded freely from the internet, and add functionality to your FreeCAD installation.

PyQt4

 * homepage: http://www.riverbankcomputing.co.uk/pyqt
 * license: GPL 2 & 3
 * optional, but needed by several modules: Draft, Arch, Ship, Plot, OpenSCAD, Spreadsheet

PyQt is required by several modules of FreeCAD to access FreeCAD's Qt interface. It is already bundled in the windows verison of FreeCAD, and is usually installed automatically by FreeCAD on Linux, when installing from official repositories. If those modules (Draft, Arch, etc) are enabled after FreeCAD is installed, it means PyQt is already there, and you don't need to do anything more.

Note:

PyQt4 will be progressively obsoleted in FreeCAD after version 0.13, in favour of PySide, which does exactly the same job but has a license (LGPL) more compatible with FreeCAD.

Linux
The simplest way to install PyQt4 is through your distribution's package manager. On Debian/Ubuntu systems, the package name is generally python-qt4, while on RPM-based systems it is named pyqt4. The necessary dependencies (Qt and SIP) will be taken care of automatically.

Windows
The program can be downloaded from http://www.riverbankcomputing.co.uk/pyqt/download.php. You'll need to install the Qt and SIP libraries before installing pyqt4 (to be documented).

MacOSX
PyQt on Mac can be installed via homebrew or port. See CompileOnMac for more information.

Usage
Once it is installed, you can check that everything is working by typing in FreeCAD python console:

import PyQt4

To access the FreeCAD interface, type:

from PyQt4 import QtCore,QtGui app = QtGui.qApp FreeCADWindow = app.activeWindow

Now you can start to explore the interface with the dir command. You can add new elements, like a custom widget, with commands like:

FreeCADWindow.addDockWidget(QtCore.Qt.RghtDockWidgetArea,my_custom_widget)

Additional documentation
More pyQt4 tutorials (including how to build interfaces with Qt Designer to use with python):


 * http://www.riverbankcomputing.co.uk/static/Docs/PyQt4/html/classes.html - the official PyQt4 API Reference
 * http://www.rkblog.rk.edu.pl/w/p/introduction-pyqt4/ - a simple introduction
 * http://www.zetcode.com/tutorials/pyqt4/ - very complete in-depth tutorial

Pivy

 * homepage: https://bitbucket.org/Coin3D/coin/wiki/Home
 * license: BSD
 * optional, but needed by several modules of FreeCAD: Draft, Arch

Pivy is a needed by several modules to access the 3D view of FreeCAD. On windows, Pivy is already bundled inside the FreeCAD installer, and on Linux it is usually automatically installed when you install FreeCAD from an official repository. On MacOSX, unfortunately, you will need to compile pivy yourself.

Prerequisites
I believe before compiling Pivy you will want to have Coin and SoQt installed.

I found for building on Mac it was sufficient to install the Coin3 binary package. Attempting to install coin from MacPorts was problematic: tried to add a lot of X Windows packages and ultimately crashed with a script error.

For Fedora I found an RPM with Coin3.

SoQt compiled from source fine on Mac and Linux.

Debian & Ubuntu
Starting with Debian Squeeze and Ubuntu Lucid, pivy will be available directly from the official repositories, saving us a lot of hassle. In the meantime, you can either download one of the packages we made (for debian and ubuntu karmic) availables on the Download pages, or compile it yourself.

The best way to compile pivy easily is to grab the debian source package for pivy and make a package with debuild. It is the same source code from the official pivy site, but the debian people made several bug-fixing additions. It also compiles fine on ubuntu karmic: http://packages.debian.org/squeeze/python-pivy (download the .orig.gz and the .diff.gz file, then unzip both, then apply the .diff to the source: go to the unzipped pivy source folder, and apply the .diff patch: patch -p1 < ../pivy_0.5.0~svn765-2.diff then debuild to have pivy properly built into an official installable package. Then, just install the package with gdebi.

Other linux distributions
First get the latest sources from the project's repository: hg clone http://hg.sim.no/Pivy/default Pivy As of March 2012, the latest version is Pivy-0.5.

Then you need a tool called SWIG to generate the C++ code for the Python bindings. Pivy-0.5 reports that it has only been tested with SWIG 1.3.31, 1.3.33, 1.3.35, and 1.3.40. So you can download a source tarball for one of these old versions from http://www.swig.org. Then unpack it and from a command line do (as root): ./configure make make install (or checkinstall if you use it) It takes just a few seconds to build.

Alternatively, you can try building with a more recent SWIG. As of March 2012, a typical repository version is 2.0.4. Pivy has a minor compile problem with SWIG 2.0.4 on Mac OS (see below) but seems to build fine on Fedora Core 15.

After that go to the pivy sources and call python setup.py build which creates the source files. Note that build can produce thousands of warnings, but hopefully there will be no errors.

This is probably obsolete, but you may run into a compiler error where a 'const char*' cannot be converted in a 'char*'. To fix that you just need to write a 'const' before in the appropriate lines. There are six lines to fix.

After that, install by issuing (as root): python setup.py install (or checkinstall python setup.py install) That's it, pivy is installed.

Mac OS
These instructions may not be complete. Something close to this worked for OS 10.7 as of March 2012. I use MacPorts for repositories, but other options should also work.

As for linux, get the latest source: hg clone http://hg.sim.no/Pivy/default Pivy If you don't have hg, you can get it from MacPorts: port install mercurial

Then, as above you need SWIG. It should be a matter of: port install swig

I found I needed also: port install swig-python

As of March 2012, MacPorts SWIG is version 2.0.4. As noted above for linux, you might be better off downloading an older version. SWIG 2.0.4 seems to have a bug that stops Pivy building. See first message in this digest: https://sourceforge.net/mailarchive/message.php?msg_id=28114815

This can be corrected by editing the 2 source locations to add dereferences: *arg4, *arg5 in place of arg4, arg5. Now Pivy should build: python setup.py build sudo python setup.py install

Windows
Assuming you are using Visual Studio 2005 or later you should open a command prompt with 'Visual Studio 2005 Command prompt' from the Tools menu. If the Python interpreter is not yet in the system path do set PATH=path_to_python_2.5;%PATH%

To get pivy working you should get the latest sources from the project's repository: svn co https://svn.coin3d.org/repos/Pivy/trunk Pivy Then you need a tool called SWIG to generate the C++ code for the Python bindings. It is recommended to use version 1.3.25 of SWIG, not the latest version, because at the moment pivy will only function correctly with 1.3.25. Download the binaries for 1.3.25 from http://www.swig.org. Then unpack it and from the command line add it to the system path set PATH=path_to_swig_1.3.25;%PATH% and set COINDIR to the appropriate path set COINDIR=path_to_coin

On Windows the pivy config file expects SoWin instead of SoQt as default. I didn't find an obvious way to build with SoQt, so I modified the file setup.py directly. In line 200 just remove the part 'sowin' : ('gui._sowin', 'sowin-config', 'pivy.gui.') (do not remove the closing parenthesis).

After that go to the pivy sources and call python setup.py build which creates the source files. You may run into a compiler error several header files couldn't be found. In this case adjust the INCLUDE variable set INCLUDE=%INCLUDE%;path_to_coin_include_dir and if the SoQt headers are not in the same place as the Coin headers also set INCLUDE=%INCLUDE%;path_to_soqt_include_dir and finally the Qt headers set INCLUDE=%INCLUDE%;path_to_qt4\include\Qt

If you are using the Express Edition of Visual Studio you may get a python keyerror exception. In this case you have to modify a few things in msvccompiler.py located in your python installation.

Go to line 122 and replace the line vsbase = r"Software\Microsoft\VisualStudio\%0.1f" % version with vsbase = r"Software\Microsoft\VCExpress\%0.1f" % version Then retry again. If you get a second error like error: Python was built with Visual Studio 2003;... you must also replace line 128 self.set_macro("FrameworkSDKDir", net, "sdkinstallrootv1.1") with self.set_macro("FrameworkSDKDir", net, "sdkinstallrootv2.0") Retry once again. If you get again an error like error: Python was built with Visual Studio version 8.0, and extensions need to be built with the same version of the compiler, but it isn't installed. then you should check the environment variables DISTUTILS_USE_SDK and MSSDK with echo %DISTUTILS_USE_SDK% echo %MSSDK% If not yet set then just set it e.g. to 1 set DISTUTILS_USE_SDK=1 set MSSDK=1

Now, you may run into a compiler error where a 'const char*' cannot be converted in a 'char*'. To fix that you just need to write a 'const' before in the appropriate lines. There are six lines to fix. After that copy the generated pivy directory to a place where the python interpreter in FreeCAD can find it.

Usage
To check if Pivy is correctly installed:

import pivy

To have Pivy access the FreeCAD scenegraph do the following:

from pivy import coin App.newDocument # Open a document and a view view = Gui.ActiveDocument.ActiveView FCSceneGraph = view.getSceneGraph # returns a pivy Python object that holds a SoSeparator, the main "container" of the Coin scenegraph FCSceneGraph.addChild(coin.SoCube) # add a box to scene

You can now explore the FCSceneGraph with the dir command.

Additonal Documentation
Unfortunately documentation about pivy is still almost inexistant on the net. But you might find Coin documentation useful, since pivy simply translate Coin functions, nodes and methods in python, everything keeps the same name and properties, keeping in mind the difference of syntax between C and python:


 * http://doc.coin3d.org/Coin/classes.html - Coin3D API Reference
 * http://www-evasion.imag.fr/~Francois.Faure/doc/inventorMentor/sgi_html/index.html - The Inventor Mentor - The "bible" of Inventor scene description language.

You can also look at the Draft.py file in the FreeCAD Mod/Draft folder, since it makes big use of pivy.

pyCollada

 * homepage: http://pycollada.github.com
 * license: BSD
 * optional, needed to enable import and export of Collada (.DAE) files

pyCollada is a python library that allow programs to read and write Collada (*.DAE) files. When pyCollada is installed on your system, FreeCAD will be able to handle importing and exporting in the Collada file format.

Installation
Pycollada is usually not yet available in linux distributions repositories, but since it is made only of python files, it doesn't require compilation, and is easy to install. You have 2 ways, or directly from the official pycollada git repository, or with the easy_install tool.

Linux
In either case, you'll need the following packages already installed on your system:

python-lxml python-numpy python-dateutil

From the git repository
git clone git://github.com/pycollada/pycollada.git pycollada cd pycollada sudo python setup.py install

With easy_install
Assuming you have a complete python installation already, the easy_install utility should be present already:

easy_install pycollada

You can check if pycollada was correctly installed by issuing in a python console:

import collada

If it returns nothing (no error message), then all is OK

Windows
To Be Documented

Reference on how to use easy_install: http://jishus.org/?p=452

Mac OS
To Be Documented

IfcOpenShell

 * homepage: http://www.ifcopenshell.org
 * license: LGPL
 * optional, needed to extend import abilities of IFC files

IFCOpenShell is a library currently in development, that allows to import (and soon export) Industry foundation Classes (*.IFC) files. IFC is an extension to the STEP format, and is becoming the standard in BIM workflows. When ifcopenshell is correctly installed on your system, the FreeCAD Arch Module will detect it and use it to import IFC files, instead of its built-in rudimentary importer. Since ifcopenshell is based on OpenCasCade, like FreeCAD, the quality of the import is very high, producing high-quality solid geometry.

Installation
Since ifcopenshell is pretty new, you'll likely need to compile it yourself.

Linux
You will need a couple of development packages installed on your system in order to compile ifcopenshell:

liboce-*-dev python-dev swig

but since FreeCAD requires all of them too, if you can compile FreeCAD, you won't need any extra dependency to compile IfcOpenShell.

Grab the latest source code from here:

svn co https://ifcopenshell.svn.sourceforge.net/svnroot/ifcopenshell ifcopenshell

The build process is very easy:

mkdir ifcopenshell-build cd ifcopenshell-build cmake ../ifcopenshell/cmake

or, if you are using oce instead of opencascade:

cmake -DOCC_INCLUDE_DIR=/usr/include/oce ../ifcopenshell/cmake

Since ifcopenshell is made primarily for Blender, it uses python3 by default. To use it inside FreeCAD, you need to compile it against the same version of python that is used by FreeCAD. So you might need to force the python version with additional cmake parameters (adjust the python version to yours):

cmake -DOCC_INCLUDE_DIR=/usr/include/oce -DPYTHON_INCLUDE_DIR=/usr/include/python2.7 -DPYTHON_LIBRARY=/usr/lib/python2.7.so ../ifcopenshell/cmake

Then:

make sudo make install

You can check that ifcopenshell was correctly installed by issuing in a python console:

import IfcImport

If it returns nothing (no error message), then all is OK

Windows
Copied from the IfcOpenShell README file

Users are advised to use the Visual Studio .sln file in the win/ folder. For Windows users a prebuilt Open CASCADE version is available from the http://opencascade.org website. Download and install this version and provide the paths to the Open CASCADE header and library files to MS Visual Studio C++.

For building the IfcPython wrapper, SWIG needs to be installed. Please download the latest swigwin version from http://www.swig.org/download.html. After extracting the .zip file, please add the extracted folder to the PATH environment variable. Python needs to be installed, please provide the include and library paths to Visual Studio.

Teigha Converter

 * homepage: http://www.opendesign.com/guestfiles/TeighaFileConverter
 * license: freeware
 * optional, used to enable import and export of DWG files

The Teigha Converter is a small freely available utility that allows to convert between several versions of DWG and DXF files. FreeCAD can use it to offer DWG import and export, by converting DWG files to the DXF format under the hood,then using its standard DXF importer to import the file contents. The restrictions of the DXF importer apply.

Installation
On all platforms, only by installing the appropriate package from http://www.opendesign.com/guestfiles/TeighaFileConverter. After installation, if the utility is not found automatically by FreeCAD, you might need to set the path to the converter executable manually, in the menu Edit -> Preferences -> Draft -> Import/Export options.