.. _Prerequisites: Prerequisites ------------- VisIt's Source Code ~~~~~~~~~~~~~~~~~~~ For a released version """""""""""""""""""""" For building a released version of VisIt version 3.2.1 or earlier, you can download a windows installer that contains all that is necessary from the `downloads page `_. Look for the *Win 10/8/7 development* link for the particular version you want. The file will be named *visitdev3.2.1.exe* (or similar, based on version chosen). For building a released version of VisIt version 3.2.2 or newer, download the *Source* tgz file as well as the *Win 10 development* file which will be named *visit_windowsdev_3.2.2.zip* (or similar, based on version chosen). The .zip file contains all the pre-built third-party binaries needed for building VisIt on Windows. It is best to extract these files to the same folder so that *src* from the source tarball is peer to *windowsbuild* from the windows-dev zip file. For the latest development version """""""""""""""""""""""""""""""""" If you want to build the latest development version from our repository, you need to obtain source from the `visit repo `_, and the pre-built third party dependencies from the `visit-deps repo `_ on GitHub. Other Software ~~~~~~~~~~~~~~ 1. `CMake `_ version 3.24 or greater. * Don't use the CMake included with cygwin if you plan on using the pre-built thirdparty libraries. 2. Visual Studio 2022 (VisIt 3.4.0 and newer) or Visual Studio 2017 * Needed if you want to use our pre-built thirdparty libraries. 3. `NSIS `_ *Optional* * For creating an installer for VisIt. NSIS 2 or 3 should work. 4. `Microsoft MPI `_. *Optional* * For building VisIt's parallel engine. Redistributable binaries and SDK's are needed, so download and install both msmpisdk.msi and msmpisetup.exe.