So 12. Mar 11:15:43 CET 2023 in Munich (Germany), 
written by Klaus Wittig (klaus.wittig@calculix.de)


WARNING: 
The cgx program knows the "sys" command which is used to issue any shell
command (unix or dos shell). For example to move files created by the 'send'
command to certain file names or/and locations and to start the analysis. But
if you use CGX to open an untrusted fbd file downloaded from the internet, it
might delete all your files or do whatever it wants as long as cgx has the
necessary rights.
Even an honest but carelessly written fbd file could be destructive if it
makes incorrect assumptions about the locations of files. For example, by
clearing the contents of a directory to clean up, it might delete important
files on someone else's computer.

To prevent the user from executing potential dangerous 'sys' commands the
program will stop at every 'sys' command and waits for the user to either
accept each single one or to accept the execution of every future 'sys'
command by writing "ALLOW_SYS" in the .cgx file in the $HOME directory.

If this functionallity is not desired then change "ALLOW_SYS_FLAG   0" in the
cgx.h file to "ALLOW_SYS_FLAG   1". The program accepts then all 'sys' commands
w/o warnings.



                          Basic Installation
                          ==================

    If you encounter problems please read the last section "Possible
    problems and some hints" and the section "Known Problems" in the
    documentation.

    There are two ways of instalation:
    - Section A: Installation of the 64bit-binary
    - Section B: Instalation from the source:
                 recomended if you encounter problems with the binary 
                 or if your hardware is not supported.

    For full functionallity you need the following additional programs. Please
    make sure that this programs are installed in a system known location. Or
    extend the PATH variable (for example: export PATH=$PATH:$HOME/myfolder
    in your .bashrc)
    - convert, composite and mogrify (ImageMagick suite of tools)
    - pstops (from psutils)
    - firefox or any other html-browser (modify cgx.h if firefox is not avail.)
    - gv (ghostview) (modify cgx.h if gv is not available )
    - gnuplot
    - either tetgen, a command line driven tet mesher (searched by
      default). The mesher can be changed either before compilation in cgx.h or
      during run time with the command 'asgn'. You find tetgen in the package.
    - or/and ng_vol from the netgen project. Replace the src file with the
      one located in the folder cgx_2.21/netgen and build it in the netgen
      directory. This allows tet-meshing with a target-element-size.

    The cgx program evaluates the environment variables:
    - CGXDOCS which will overwrite the cgx helpfile, the default is defined in
      cgx.h
    - CCXDOCS which will overwrite the ccx helpfile, the default is defined in
      cgx.h
    - BROWSER which will overwrite the helpfile browser, the default is defined
      in cgx.h
    - CGXTERMVIEWER which will overwrite the postscript viewer, the default is
      defined in cgx.h PSVIEWER
    - CGXVIEWFORMAT which will overwrite the postscript format, the default is
      defined in cgx.h VIEWFORMAT
    The browser could also be something else as an html-browser as long as it
    supports the format of the helpfiles (for example use an pdf viewer if you
    specified pdf helpfiles)

    Be aware of the 'asgn' command which allows the (re-)definition of the above
    items during startup (if used in the .cgx file) or run-time.
    


 A: Installation of the binary
    --------------------------

 1. Get the binary and do the following
    - bunzip2 cgx_2.21.bz2 (beware your browser could scip the ending
      .bz2, then please rename the filename to the above one before unzipping )

    It is necessary to have openGL on your system!

    The libraries  
    /usr/lib64/libGL.so
    /usr/lib64/libGLU.so
    The libGLU should be the one from SGI. Otherwise the nurbs rendering is
    not supported.
    WARNING: To improve the stabillity of the GLU you may recompile the
    library (after downloading from the internet) by regarding the following
    hint:
      after  ./configure
      open Makefile and
      change:
        CFLAGS = -g -O2
        CXXFLAGS = -g -O2
      to:
        CFLAGS = -O -DNDEBUG
        CXXFLAGS = -O -DNDEBUG

    You might create links to other locations if the libraries are 
    stored at other places.

    For example:

    ln -s /usr/i486-linux-libc5/lib/libGL.so.3 /usr/lib/libGL.so

 2. login as root

 3. if possible rename the binary to /usr/local/bin/cgx
    mv cgx_2.21 /usr/local/bin/cgx
    chmod ao+rx /usr/local/bin/cgx

 4. If you like the help-system to work then please do the following:

 5. login as root if not already done.

 4. get the documentation (html) and do the following:
    - move the file containing the docu cgx_2.21.htm.tar.bz2 to /usr/local 
    - bunzip2 cgx_2.21.htm.tar.bz2 (beware sometimes the ending .bz2 is missed, 
      please rename the filename to the above one)
    - tar -xvf cgx_2.21.htm.tar
    - the html-browser must be known as "firefox"
      so if you dont have firefox you should create an link like:
      ln -s <your browser location> /usr/local/bin/firefox

 7. Check the path /usr/local/CalculiX/cgx_2.21/doc/cgx
    all the html files should be located there

 8. Check the installation, if you performed step 3. type:
    cgx -b dummy.fbd
    a window should appear on your screen.
    Go with the mouse-ponter outside the inner big black rectangle.
    Press the left mouse button. The menu will appear. Go down to "Help" and
    choose "Html Manual cgx". 
    The browser should open and the documentation should be vissible. If not be
    sure that the documentation is in /usr/local/CalculiX/cgx_2.21/doc/cgx

 9. get the examples and do the following
    - move the file cgx_2.21.exa.tar.bz2 to /usr/local 
    - bunzip2 cgx_2.21.exa.tar.bz2
    - tar -xvf cgx_2.21.exa.tar.bz2

10. get tetgen tetgen1.5.1 either from the internet or from the cgx package
    - bunzip2 cgx_2.21.all.tar.bz2
    Unpack tetgen1.5.1.tar and change to tetgen1.5.1 and run 'make'.
    Place the program tetgen at /usr/local/bin/

    Then you might change the protections:
    chmod ao+rx /usr/local/bin/tetgen


 B: Instalation from the source:
    ----------------------------

    Make sure that you have the devel packages for the graphic system
    installed (the headers for X11 etc.)

    You need openGL on your system. Check your file system for the
    two following libraries:

    The openGL-library:              libGL.so  or  libMesaGL.so
    The higher level openGL-library: libGLU.so  or  libMesaGLU.so

    The libGLU should be the one from SGI. Otherwise the nurbs rendering
    is not supported.

    On some systems the extension might also be ~.a instead of ~.so

    You might search for this files with for example "locate libGL" or 
    "find /usr/* -name libGL* -print"

    If you find only libMesaGL and libMesaGLU instead of libGL and libGLU
    you have to create a link or a copy with the names libGL and libGLU
    but ceep the extension .a or .so.

    This files should be located in:
    /usr/lib64/

    otherwhise you have to modify the file:
    /usr/local/CalculiX/cgx_2.21/src/Makefile

    The original glut package from mark Kilgard is now in the distribution and
    will be compiled with the other source files.

 1. Unpack the file cgx_2.21.all.tar.bz2 in "/usr/local".

 2. Then change to the following directory with:
    cd /usr/local/CalculiX/cgx_2.21/src

 3. Change the path names in the Makefile to the ones used on your system if
    necessary.

 4. If your installation path is not "/usr/local" then you must also change
    the path for the html-help-files in "cgx.h",
    see parameter "HELPFILE". If your web-browser is not firefox change the 
    parameter "BROWSER" also.

 5. run "make" as root. On 32bit PCs you have to modify the Makefile. 
    Change lib64 to lib below LFLAGS .
    If you have trouble with c++ code use Makefile_pure_c to use only c code.
    But you will not be able to deal with nurbs any more.

    Then copy the binary "cgx" to
    "/usr/local/bin/cgx" with:
    cp cgx /usr/local/bin/cgx

    If /usr/local/bin does not exist, create it with:
    mkdir /usr/local/bin

    Then you might change the protections:
    chmod ao+rx /usr/local/bin/cgx

 6. If you have "latex" and "latex2html" on your system then run "latex cgx" 
    in "/usr/local/CalculiX/cgx_2.21/doc" (run it 3 times!!!) and then run
    "latex2html cgx". 
    This creates the html-help-files. Alternatively you might download them
    as well. Then get cgx_2.21.htm.tar.bz2 and unpack this package in 
    /usr/local/.

 7. The program needs to write an info file to your home directory during run 
    time. Be sure that "HOME" is defined and that you have write permission to
    this directory. Type "echo $HOME" and check your permissions for the 
    printed directory.

 8. Unpack tetgen1.5.1.tar and change to tetgen1.5.1 and run 'make'.
    Place the program tetgen at /usr/local/bin/

    Then you might change the protections:
    chmod ao+rx /usr/local/bin/tetgen

 9. Check the installation, type:
    cgx -b dummy.fbd
    and a window should appear on your screen.
    Go with the mouse-ponter outside the inner black rectangle.
    Press the left mouse button. The menu will appear. Go down to "Help" and
    choose "Html Manual (cgx)". 
    The browser should open and the documentation should be vissible. If not be
    sure that the documentation is in /usr/local/CalculiX/cgx_2.21/doc/cgx



    Possible problems and some hints:
    ---------------------------------

    If you get some errors regarding threading (meshing) then
    delete all *.o and change in Makefile
    CFLAGS = -O2 -Wall -Wno-narrowing -DSEMINIT \
    to
    CFLAGS = -O2 -Wall -Wno-narrowing \
    and recompile with make
 
    If you get some linker errors then you may have multiple libGL,
    libglut or libGLU on your system.

    If commands like "plot n all" are not recognized by the program
    then your mouse pointer was probably not in the main window during 
    typing {;->)
 
    If the loader complains that a specific lib is not there, then a 
    newer version may be available. Create a link with the required name to the 
    new lib (ln -s new-lib-name old-lib-name).

    If the command 'rep all' causes a segmentation fault it may be solved by
    using a manually compiled version of libGLU. Regard the hints written
    under section 1.

    If tet-meshing fails with the following messages:
     ERROR: The input file "test.vol" could not be opened.
     ERROR: No mesh-file found
    then ng_vol from the netgen project might not be available or the surface-
    mesh is not closed.

    No tetmesh is created. Please make sure that you had installed tetgen or
    ng_vol (see section Basic Installation). You find tetgen in the package.
 
Good luck,

Klaus Wittig