JSONCPP is required to build a VRPN server for the Vrpn Android widgets (see android_widgets directory). If you've done a recursive clone, JSONCPP is in the submodules directory, will be built automatically, and you can completely ignore the rest of this file. Get the latest JSONCPP (r156 has been used successfully) from http://jsoncpp.svn.sourceforge.net/svnroot/jsoncpp/trunk/jsoncpp You will also need Scons and Python To build jsoncpp, see README.txt in the JSONCPP directory, but : 1/ Get scons-local (2.0.1 is OK) from http://www.scons.org/download.php instead of the link in the README, then extract scons-local into the jsoncpp directory as mentionned in the README 2/ To avoid LNK2005 errors when building VRPN, you will need to edit jsoncpp/Sconstruct locate the section relative to your build environment, for instance : elif platform == 'msvc90': in this instruction block, replace the line : env['CXXFLAGS']='xxxxxxx /MT' by : env['CXXFLAGS']='xxxxxxx /MD' 3/ To build with Visual Studio, run the Visual Studio command that configures environment variables (on VS-2008-32, look for a file named vsvars32.bat), otherwise scons may not find the compiler Then build, for instance with the command c:\Python27\python.exe scons.py platform=msvc90 The values allowed for platform are suncc vacpp mingw msvc6 msvc7 msvc71 msvc80 msvc90 linux-gcc WARNING: the JSONCPP build system builds a Release version. Using this release library with a Debug VRPN server crashes. To clean, use the command c:\Python271\python.exe scons.py platform=msvc90 -c Then, run CMAKE for VRPN, define VRPN_USE_JSONNET and JSONCPP_ROOT_DIR.