Hello all,

Solidworks Help states the following regarding shell meshes:

To distinguish the top and bottom faces of the shell elements, SolidWorks Simulation assigns different colors to top and bottom faces of generated shells.

Indeed, shell elements have a grey and an orange side. Unforunately, there are no details whatsoever which leaves me to ponder the following questions, which I hope some of you will be able to answer:

• Which color is the top? Which is the bottom? Why does it matter enough to make a distinction?
  
• Elements require a user-defined shell thickness. Does the software assume the element is located at the mid plane or on one of the surfaces of the simulated part? If the latter is true, does the element thickness grow out of the grey side or the orange side?
  
• Under what circumstances should I use the 'Flip Shell Elements' command?
  

Thanks in advance for any insight,

Joe