use displacement and then bake it. Or if it's nurbs you could use this script of mine:

global proc displaceCVs(float $minVal, float $maxVal)
{
$sel = `ls -sl`;

$Udiv = `getAttr $sel".spansU"`;
$Vdiv = `getAttr $sel".spansV"`;

//loop through the CVs and add random amounts to their y direction.

$i = 0;
for($i = 0; $i < $Udiv; $i++)
{
$j = 0;
for($j = 0; $j < $Vdiv; $j++)
{
select -r $sel.cv[$i][$j];
float $displace = `rand $minVal $maxVal`;
xform -r -t 0 $displace 0 ;
}
}
}


If you've got a poly surface it's the same idea.

Alan