This tutorial explains how to extrude those curves into 3d objects manually. There are other ways to achieve the same effect using built in functionality found in the various menus that Maya has.
This is the script. Just select the faces on your model you want to separate and then run the script:
polyChipOff -ch 1 -kft 1 -dup 0 -off 0;
string $nemSelected[] = `selectedNodes`;
polySeparate -ch 1 $nemSelected;