• installer: install the program with administrator privileges.
  • zip: simply uncompress the archive; Molekel.exe is in molekel/bin.


Uncompress the archive and add the molekel/lib directory to LD_LIBRARY_PATH then run <molekel root>/bin/Molekel:

sh: export LD_LIBRARY_PATH=<molekel installation dir>/lib:$LD_LIBRARY_PATH

csh: setenv LD_LIBRARY_PATH <molekel installation dir>/lib:${LD_LIBRARY_PATH}

If you get an error similar to the following:

.../lib/tls/ version 'GLIBC_2.4' not found (required by ./lib/

it means you do not have glibc 2.4 installed, you can either install glibc 2.4 o simply download this patch and replace <molekel root>/lib/ with the version found in the archive which works with glibc 2.3.

Launch from desktop

To be able to launch Molekel from KDE and Gnome you can create a script like:

#if you have not added the command to add Molekel's dynamic libs dir to LD_LIBRARY_PATH
#to your .profile or .tcshrc file you need to do it here:
export LD_LIBRARY_PATH=<molekel installation dir>/lib:$LD_LIBRARY_PATH
#launch molekel
<molekel installation dir>/bin/Molekel

You can change the icon of the desktop shortcut by selecting the Molekel.png icon in the <molekel root>/resources directory.

Mac OS

Simply open the dmg disk image and copy the folders to any location; you may want to create a Molekel folder inside Applications and put everything there.

Rendering issues

Molekel versions 5.3 or above use some advanced multi-pass rendering techniques to enhance visual quality; these techniques may generate visual artifacts on transparent surfaces on some specific graphic cards. We have experienced problems on SuSE 10.3 x86-32/NVIDIA 8800 Ultra and Windows XP 32bit/NVIDIA 8800 Ultra systems; on Windows problems can be fixed by selecting Let the 3D application decide (which should be the default) in the Image Settings page of the NVIDIA Control Panel.

In general, in case you have rendering problems, get messages about errors in Coin or the program crashes when loading files without reporting any error, you can set the value of two environment variables as follows:


before launching Molekel to disable the use of advanced OpenGL features.

To set the environment variables permanently on Windows XP right-click on My Computer then select the Advanced tab and click on the Environment Variables button.

You can also set the COIN_DEBUG_GLGLUE environment variable to 1 before starting Molekel in a console window to print OpenGL debug information. To enable printing on standard output on Mac you'll have to invoke the actual executable in the folder i.e.