Ok, Sorted this one out, It was simple. http://stackoverflow.com/questions/11684954/can-function-default-template-parameter-be-put-before-non-default-ones -- View this message in context: http://itk-users.7.n7.nabble.com/NthElement-Image-output-tp32683p32693.html Sent from the ITK - Users mailing list archive at Nabble.com.