
   Access via TOOLS - OPTIONS on the main menu.

   The 'Options' panel allows:

   1.  Default setting of the maximum number of faces 
       traversed when a ray is traced through a crystal.  
       The normal value is about six.  the maximum value 
       is 18 and if a greater number is entered zero is 
       returned.

       The maximum number of faces is also stored with 
       simulation parameters 9including the startup file 
       so this value can change as HALOSIM is operated.

   2.  Default options for colour simulation plotting.

   3.  Default setting of symmetry controls.   These are 
       best left permanently on.

   4.  Visibility of some controls to be customised.  Some
       controls are rarely udes and so may be hidden.

   5.  Contol of how the Control Panel operates.

   6.  Autosave of parameters and simulations to be 
       enabled or disabled.

   7.  Multisave - intermediate automatic saving of 
       simulations at intervals as rays are plotted - to 
       be enabled.

   8.  Saving of simulation parameters to be with or 
       without a description.   


   RESTORE INSTALLATION DEFAULTS - restores the option 
   settings that existed when HALOSIM was installed.

   USE THIS SESSION - The chosen options operate until the
   program is closed.

   SAVE AS DEFAULTS - The options operate from then on 
   in the session and when the program is subsequently 
   used.

   CANCEL - Any changes to the options are ignored and 
   the previous settings are restored

   Parts of the Options panel freeze during a simulation.  
   This is because changes of some parameters would 
   corrupt the simulation or crash the program.

