Have you selected the mesh first then press the 3 button, if that does not work show us your mesh.......dave Edit:What maya version are you using, I think from maya 2009 onwards the 3 button works I selected sphere polygon for example then I pressed the 3 on keyboard then I got rendering with mental ray. this picture shows version and problem. please help https://imageshack.us/photo/my-images/404/pic22t.jpg/