DEFINE_SURFACE_REGIONS
{
    world.big_object.box3[GAUCHE]
    {
        INCLUDE_ELEMENTS = [LEFT]
        SURFACE_CLASS = m_sc_4
    }
    world.big_object.box3[DROIT]
    {
        INCLUDE_ELEMENTS = [RIGHT]
        MOLECULE_NUMBER
        {
            s_g_0' = 500
        }
    }
}

MODIFY_SURFACE_REGIONS
{
    world.big_object.box3[GAUCHE]
    {
        MOLECULE_NUMBER
        {
            s_g_4, = 500
        }
    }
}