NuTo is a general, openSource numerics tool. The main feature is a Finite Element Toolbox for continuum mechanics problems (including XFEM, multiscale etc.). In addition, several other toolboxes including metamodels (Bayes neural networks) or linear algebra (based on the eigen library) are included. These toolboxes can be combined an accessed either via a Python interface (generated with SWIG) are directly using the c++ interface.
The installation of nuto requires several external libraries. In addition, the source code has to be downloaded from the subversion repository and compiled. This requires a c++ and fortran compiler (gfortran and g++). Currently, the installation is only tested under Linux, though the build system is set up using cmake which enables a simple compilation under Windows (with the appropriate compilers, e.g. from intel). The details of the installation are explained here.
The results can be visualized with different tools. For a graphical output of stresses, displacements etc., an vtk or vtu output is provided, which can be rendered using paraview.
For diagrams like stress-strain, load-displacement or load-time plots, gnuplot is an interesting tool (though you could use any other tool like Excel, matlab, etc.).