If the fog appears with streaks, or the entire effect disappears from your scene when rendering in mental ray for Maya, you
            can use one of the following solutions.
         
         
          
            Solution 2
            
 
            
               - In the  for the volume primitive shape node, turn on .
               
- Set the value to 5, or greater (between 5 - 20 is recommended). (You may need to tune this setting repeatedly, until you achieve a
                  good result.)
               
- Turn on .
               
- Render your scene.