Toggle Smooth mesh of all obejects in your scene Mel Script for Maya

You can paste this right into the command window of a shelf button:

select -cl;

SelectAll;

string $sel[] =`ls -sl`;

for ($thisObj in $sel){

int $displaylevel[] = `displaySmoothness -query -polygonObject $thisObj`;

if ($displaylevel[0] == 1)

{

//Go to 3

displaySmoothness -polygonObject 3;

}

if ($displaylevel[0] == 3)

{

//Go to 1

displaySmoothness -polygonObject 1;

}

    }