IfcPlusPlus

From FreeCAD Documentation
Revision as of 04:41, 21 August 2020 by Vocx (talk | contribs) (→‎Installation of the compiled libraries: In certain systems libcarve.so may not be found by the library loader ld.so if it is installed in the default /usr/local/lib directory.)
This page is a work in progress. Please do not edit or translate until this message is removed.
Other languages:

Description

IFC++ or IfcPlusPlus is a C++ open source (MIT license) library from the IfcQuery project for reading, writing, and viewing IFC files.

The IFC++ library can be used for general purpose, and it also includes a sample IFC visualization application. This viewer is based on Qt 5 and OpenSceneGraph (OSG), and can load big IFC files very fast, and thus can be used to compare the performance of other IFC viewers, like Blender and FreeCAD, which internally use the IfcOpenShell library.

Installing

The IFC++ distribution is provided as source code, so to use the library and the viewer, the code must be compiled before it can be used.

IFC++ is developed mostly on a Windows platform, so it includes solution files (.snl) to compile the IfcPlusPlus.dll dynamic library using Visual Studio. A static library libIfcPlusPlus.a can also be produced for Linux using CMake.

Compiling in Windows

Follow the instructions in the official ifcplusplus repository.

Compiling in Linux

The general instructions are as follows:

  1. Get the source code of IFC++ from its main repository.
  2. Gather all dependencies for compiling, including a C++ compiler, CMake, and Make, and the development files for Boost, Qt 5, as well as the OpenSceneGraph (OSG) library for visualization.
  3. Run cmake to generate a Makefile, then start the compilation by running make.
  4. Install the libIfcPlusPlus.a and libcarve.so libraries to the appropriate library path so that they are found by the IFC++ sample viewer.

Prerequisites

In a Debian/Ubuntu based distribution, getting the required development files is usually simple.

sudo apt install git cmake gcc g++ libboost-all-dev
sudo apt install qt5-qmake qtbase5-dev qttools5-dev libqt5widgets5 libqt5opengl5-dev

Get the source code of the project and place it in a custom directory to which you have full write access.

git clone https://github.com/ifcquery/ifcplusplus ifcplusplus-source

OpenSceneGraph

OpenSceneGraph (OSG) is a collection of C++ libraries that uses OpenGL for 3D visualization; it can be used in games, virtual reality, scientific visualization and modelling.

sudo apt install libopenscenegraph-3.4-dev

If the files are too old in your distribution, you may also compile the libraries yourself. The procedure is outlined in the main repository, openscenegraph/OpenSceneGraph. Compiling is straight forward, although you may need various dependencies like Qt 5, Freetype, Inventor, OpenEXR, COLLADA, ZLIB, GDAL, FFmpeg, Gstreamer, SDL, and Poppler.

git clone https://github.com/openscenegraph/OpenSceneGraph OpenSceneGraph-source

mkdir -p OpenSceneGraph-build
cd OpenSceneGraph-build
cmake ../OpenSceneGraph-source

make -j 3
sudo make install

Carve

Carve is a constructive solid geometry (CSG) C++ library designed to perform boolean operations between two arbitrary polygonal meshes. Together with the IFC++ library, libIfcPlusPlus.a, Carve is used by the IFC++ sample viewer to open and display IFC files.

  • Original repository: carve, GPL2, from 2009 to 2011.
  • New repository: folded/carve, from 2011 onwards; the project changed to the MIT License starting on October, 2015.

As the project is now MIT licensed, copies of the Carve source files are now included in the IFC++ repository. This means that when compiling IFC++, libcarve.so will be compiled as well. This library must be available in the system for the IFC++ sample viewer to work properly.

CMake configuration

It is recommended to perform the configuration and compilation in a specific build directory separate from the source directory.

mkdir -p ifcplusplus-build
cd ifcplusplus-build

cmake ../ifcplusplus-source/

Actual compilation

If there were no error messages during configuration with CMake, a Makefile should have been created in the build directory, so you can proceed to compile the libraries by running make.

make -j N

N is the number of processors that you assign to the compilation process; choose at least one fewer than the total number of CPU cores that you have.

Testing the compilation in the build directory

If the build was successful you should have a Release/ subdirectory with the newly compiled libraries.

Release/libcarve.so
Release/libIfcPlusPlus.a
Release/SimpleViewerExample

You can launch the SimpleViewerExample executable with an IFC file as input.

Release/SimpleViewerExample IfcOpenHouse.ifc

Installation of the compiled libraries

If the compilation doesn't report any errors, you may run make install to copy the headers, compiled libraries, and binaries to their corresponding installation directories.

sudo make install

By default, the CMAKE_INSTALL_PREFIX is /usr/local/, so all compiled files will be placed under this directory, which normally requires elevated privileges.

/usr/local/bin/SimpleViewerExample
/usr/local/lib/libcarve.so
/usr/local/lib/libIfcPlusPlus.a
/usr/local/include/carve/*.{h, hpp}
/usr/local/include/ifcpp/geometry/*.h
/usr/local/include/ifcpp/geometry/Carve/*.h
/usr/local/include/ifcpp/geometry/OCC/*.h
/usr/local/include/ifcpp/IFC4/*.h
/usr/local/include/ifcpp/IFC4/include/*.h
/usr/local/include/ifcpp/model/*.h
/usr/local/include/ifcpp/reader/*.h
/usr/local/include/ifcpp/writer/*.h
/usr/local/share/IFCPP/cmake/*.cmake

Library path

In certain systems libcarve.so may not be found by the library loader ld.so if it is installed in the default /usr/local/lib directory.

If this is the case, you may have to update the cache of libraries:

sudo ldconfig

Or you may have to move it to the correct directory first:

sudo mkdir -p /usr/local/lib/x86_64-linux-gnu/
sudo mv /usr/local/lib/libcarve.so /usr/local/lib/x86_64-linux-gnu/libcarve.so
sudo ldconfig

Alternatively, you may set the LD_LIBRARY_PATH variable to the right directory before launching the executable:

LD_LIBRARY_PATH=/usr/local/lib SimpleViewerExample

To make this change permanent, this environmental variable can be set in the corresponding .bashrc resource file, so that it is propagated to all terminal instances:

export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

Removing the compiled libraries

To remove the installed libraries, just remove the corresponding files that were installed.

sudo rm -rf /usr/local/bin/SimpleViewerExample
sudo rm -rf /usr/local/lib/libcarve.so
sudo rm -rf /usr/local/lib/libIfcPlusPlus.a
sudo rm -rf /usr/local/include/carve
sudo rm -rf /usr/local/include/ifcpp
sudo rm -rf /usr/local/share/IFCPP/cmake/

Links