1 Introduction

Bil is a modeling platform based on finite element/volume methods dedicated to coupled problems involved in environmental engineering, geomechanical engineering, material sciences, etc.. Bil is distributed under the terms of the GNU General Public License (GnuGPL). The source code can be downloaded at

Bil is intended to be used by students, engineers or reseachers to work out problems or develop their own models. Bil is written in C language. Thus provided that a C compiler was installed, it can run on any OS. However the complete installation of Bil (including documentations) can be achieved on Linux-based OS only (Debian, Ubuntu, etc..).

Bil is developped for 1D, 2D and 3D problems. It doesn’t include a mesh generator and post-processing treatment of outputs. However it can read mesh files created by the open-source free software Gmsh downloadable at http://www.geuz.org/gmsh/. The output files created by Bil for 1D problems can be used easily by some plotting programs as Gnuplot. But as a general rule, post-processing options create output files which can be used by Gmsh for post-processing treatments (see Bil options).