# Documentation/4.2/Developers/Build Instructions/Configure

Home < Documentation < 4.2 < Developers < Build Instructions < Configure

## CONFIGURE and generate Slicer solution files

You can configure and generate Slicer solution files using either ccmake or cmake-gui.

### Per-platform instructions

#### Windows

• Recommended: cmake-gui
• Configure using default options.
• Set the build directory. For example: C:\Slicer4-SuperBuild-Debug or C:\Slicer4-SuperBuild-Release
• Remarks:
1. If you downloaded the Qt binary then qmake will be detected and all paths will be set automatically.
2. If you built your own Qt (e.g. in Debug mode for use with the designer) set the QT_QMAKE_EXECUTABLE in cmake-gui.QT_QMAKE_EXECUTABLE should be set to the path of the qmake.exe file, which is inside the bin directory (for example, \path\to\qt-everywhere-opensource-build-4.7.4\bin\qmake.exe).
3. Windows doesn't support path longer than 260 characters, please make sure that the total path name of your Slicer-build directory is no longer than 50 characters ( for example c:\work\Slicer\Slicer-Superbuild (32 characters) is fine)

#### Unix-like

• Recommended: ccmake
• Configure using the following commands. By default CMAKE_BUILD_TYPE is set to Debug.
mkdir Slicer4-SuperBuild-Debug
cd Slicer4-SuperBuild-Debug
ccmake -DQT_QMAKE_EXECUTABLE:FILEPATH=/path/to/QtSDK-1.2/Desktop/Qt/474/gcc/bin/qmake ../Slicer


where you replace /path/to with the real path on your machine where QtSDK-1.2 is located

• Remarks:
1. Using top-level directory name like Slicer-Superbuild-Release or Slicer-Superbuild-Debug is recommended.
2. Once the project is configured with cmake, generate it

### General information

Two projects are generated by either cmake, ccmake or cmake-gui.

One of them is in the top-level bin directory Slicer4-Superbuild and the other one is in the subdirectory Slicer-build:

Slicer4-Superbuild/Slicer-build
1. The first project in Slicer4-Superbuild manages all the external dependencies of Slicer (VTK, ITK, Python, ...). To build Slicer for the first time, run make (or build the solution file in Visual Studio) in Slicer4-Superbuild, which will update and build the external libraries and if successful will then build the subproject Slicer-build.
2. The second project in Slicer4-Superbuild/Slicer-build is the "traditional" build directory of Slicer. After local changes in Slicer (or after an svn update on the source directory of Slicer), only running make (or building the solution file in Visual Studio) in Slicer4-Superbuild/Slicer-build is necessary (the external libraries are considered built and up to date).
3. Warning: An significant amount of disk space is required to compile Slicer in Debug (>10GB on Windows)

### Workaround firewall blocking git protocol

• Some firewall will be blocking the git protocol, a possible workaround is to configure Slicer disabling the option Slicer_USE_GIT_PROTOCOL. Then http protocol will be used instead. Consider also reading https://github.com/commontk/CTK/issues/33

• By default, if CMake finds Java on your machine, it automatically builds Java CLIs. If you don't want any Java in your Slicer (or if you don't want to install Java on your Mac Os X), you can pass -DCMAKE_DISABLE_FIND_PACKAGE_Java:BOOL=TRUE when configuring Slicer.
• Same applies for OpenSSL: CMAKE_DISABLE_FIND_PACKAGE_OpenSSL:BOOL=TRUE can be passed when building Slicer for packaging.