Before building OCCT, make sure to have all required third-party libraries installed. The list of required libraries depends on what OCCT modules will be used, and your preferences. The typical minimum is FreeType (necessary for Visualization) and Tcl/Tk (for DRAW). See requirements on 3rdparty libraries for a full list.

The easiest way to install third-party libraries is to download archive with pre-built binaries, corresponding to your target configuration, from Development Portal. You can also build third-party libraries from their sources, see Build 3rd-parties for instructions.

On Linux and macOS we recommend to use libraries maintained by distributive developers, when possible.

This chapter describes the CMake-based build process, which is now suggested as a standard way to produce the binaries of Open CASCADE Technology from sources. OCCT requires CMake version 3.1 or later.

CMake is a tool that generates the actual project files for the selected target build system (e.g. Unix makefiles) or IDE (e.g. Visual Studio 2010). Here we describe the build procedure on the example of Windows platform with Visual Studio 2010. However, CMake is cross-platform and can be used to build OCCT on Linux and macOS in essentially the same way.

CMake deals with three directories: source, build or binary and installation.

The good practice is not to use the source directory as a build one. Different configurations should be built in different build directories to avoid conflicts. It is however possible to choose one installation directory for several configurations of OCCT (differentiated by platform, bitness, compiler and build type), for example:

For unexperienced users we recommend to start with cmake-gui – a cross-platform GUI tool provided by CMake on Windows, Mac and Linux. A command-line alternative, ccmake can also be used.

If the command-line tool is used, run the tool from the build directory with a single argument indicating the source (relative or absolute path) directory, and press c to configure:

If the GUI tool is used, run this tool without additional arguments and after that specify the source directory by clicking Browse Source and the build (binary) one by clicking Browse Build:

Once the source and build directories are selected, "Configure" button should be pressed in order to start manual configuration process. It begins with selection of a target configurator. It is "Visual Studio 10 2010 Win64" in our example.

Once "Finish" button is pressed, the first pass of the configuration process is executed. At the end of the process, CMake outputs the list of environment variables, which have to be properly specified for successful configuration.

The error message provides some information about these variables. This message will appear after each pass of the process until all required variables are specified correctly.

The change of the state of some variables can lead to the appearance of new variables. The new variables appeared after the pass of the configuration process are highlighted with red color by CMake GUI tool.

The following table gives the full list of environment variables used at the configuration stage:

If 3RDPARTY_DIR directory is defined, then required 3rd party binaries are sought in it, and default system folders are ignored. The procedure expects to find binary and header files of each 3rd party product in its own sub-directory: bin, lib and include. The results of the search (achieved on the next pass of the configuration process) are recorded in the corresponding variables:

The search process is as follows:

If a variable of any level is not defined (empty or -NOTFOUND) and the upper level variable is defined, the content of the non-defined variable will be sought at the next configuration step. If the search process at level 3 does not find the required files, it seeks in default places.

If a search result (include path, or library path, or dll path) does not meet your expectations, you can change 3RDPARTY__*_DIR variable, clear (if they are not empty) 3RDPARTY__DLL_DIR, 3RDPARTY__INCLUDE_DIR and 3RDPARTY__LIBRARY_DIR variables (or clear one of them) and run the configuration process again.

At this time the search will be performed in the newly identified directory and the result will be recorded to corresponding variables (replace old value if it is necessary). For example, 3RDPARTY_FREETYPE_DIR variable

can be changed to

During the configuration process the related variables (3RDPARTY_FREETYPE_DLL_DIR, 3RDPARTY_FREETYPE_INCLUDE_DIR and 3RDPARTY_FREETYPE_LIBRARY_DIR) will be filled with new found values.

Once the configuration process is done, the "Generate" button is used to prepare project files for the target IDE. In our exercise the Visual Studio solution will be automatically created in the build directory.

Go to the build folder, start the Visual Studio solution OCCT.sln and build it by clicking Build -> Build Solution.

By default, the build solution process skips the building of the INSTALL and Overview projects. When the building process is finished build:

For this, right-click on the Overview/INSTALL project and select Project Only -> Build Only -> Overview/INSTALL in the solution explorer.

Installation is a process of extracting redistributable resources (binaries, include files etc) from the build directory into the installation one. The installation directory will be free of project files, intermediate object files and any other information related to the build routines.

Normally you use the installation directory of OCCT to link against your specific application. The directory structure is as follows:

If CMake installation flags are enabled for the 3rd party products (e.g. INSTALL_FREETYPE), then the corresponding binaries will be copied to the same bin(d) and lib(d) directories together with the native binaries of OCCT. Such organization of libraries can be especially helpful if your OCCT-based software does not use itself the 3rd parties of Open CASCADE Technology (thus, there is no sense to pack them into dedicated directories).

The installation folder contains the scripts to run DRAWEXE (draw.bat or draw.sh), samples (if they were installed) and overview.html (short-cut for installed OCCT overview documentation).

This section describes the steps to build OCCT libraries for Android from a complete source package with GNU make (makefiles). The steps on Windows 7 and Ubuntu 15.10 are similar. There is the only one difference: makefiles are built with mingw32-make on Windows and native GNU make on Ubuntu.

Required tools (download and install if it is required):

Run GUI tool provided by CMake and:

Click Configure button. It opens the window with a drop-down list of generators supported by CMake project. Select "MinGW MakeFiles" item from the list

If ANDROID_NDK environment variable is not defined in current OS, add cache entry ANDROID_NDK (entry type is PATH) – path to the NDK folder ("Add Entry" button):

If on Windows the message is appeared: "CMake Error: CMake was unable to find a build program corresponding to "MinGW Makefiles" CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.", specify CMAKE_MAKE_PROGRAM to mingw32-make executable.

How to configure OCCT, see Configure section taking into account the specific configuration variables for Android:

Click Generate button and wait until the generation process is finished. Then makefiles will appear in the build folder (e.g. D:/tmp/occt-android ).

Open console and go to the build folder. Type "mingw32-make" (Windows) or "make" (Ubuntu) to start build process:

mingw32-make

or

make

Parallel building can be started with using -jN argument of "mingw32-make/make", where N is the number of building threads:

mingw32-make -j4

or

make -j4

Type "mingw32-make/make" with argument "install" to place the libraries to the install folder:

mingw32-make install

or

make install

genproj is a legacy tool (originated from command "wgenproj" in WOK) for generation of Visual Studio, Code::Blocks, Qt Creator (qmake), and XCode project files for building Open CASCADE Technology. These project files are placed inside OCCT directory (in adm subfolder) and use relative paths, thus can be moved together with sources. The project files included in official distribution of OCCT are generated by this tool.

genproj is a less flexible alternative to use of CMake build system (see Building with CMake tool), but still has some small features useful for OCCT development.

The environment is defined in the file custom.sh (on Linux and macOS) or custom.bat (on Windows) which can be edited directly:

Alternatively, you can launch genconf, a GUI tool allowing to configure build options interactively. That tool will analyze your environment and propose you to choose available options:

Below are screenshots of genconf tool on various platforms (Windows and Linux):

Click "Save" to store the specified configuration in custom.bat (Windows) or custom.sh (other systems) file.

Launch genproj to update content of inc folder and generate project files after changes in OCCT code affecting layout or composition of source files.

Note that if custom.bat is not present, genproj will start genconf to configure environment.

Launch msvc.bat to start Visual Studio with all necessary environment variables defined, and build the whole solution or required toolkits.

The MSVC project files are located in folders adm\msvc\vc.... Binaries are produced in win32 or win64 folders.

To start DRAW, launch draw.bat.

Code::Blocks is a cross-platform IDE which can be used for building OCCT on Linux, macOS and Windows platforms. The generated Code::Blocks project could be found within subfolder adm//cbp.

To start Code::Blocks, launch script codeblocks.sh. To build all toolkits, click Build->Build workspace in the menu bar.

To start DRAWEXE, which has been built with Code::Blocks on Mac OS X, run the script

Option d is used if OCCT has been built in Debug mode.

XCode is an IDE for development on macOS platform and targeting macOS and iOS platforms. genproj tool comes with a legacy XCode project files generator, but CMake is a preferred way for building OCCT on macOS platform.

To start XCode, launch script xcode.sh. To build a certain toolkit, select it in Scheme drop-down list in XCode toolbar, press Product in the menu and click Build button.

To build the entire OCCT:

To start DRAWEXE, which has been built with XCode on Mac OS X, perform the following steps:

1.Open Terminal application 2.Enter :

3.Run the script

Option d is used if OCCT has been built in Debug mode.