Invert normals, and make them look like holes..

Hey guys, I have some issues here, as the title says I cant pull that off, I want to do as here says:

http://www.vimeo.com/5738519

Thats an awesome tut…

Well the thing is, I duplicate some faces from a mesh, then im supposed to extrude em, then just invert the normals, but nothing happens…I really dont know what to do…please guys any help woulb be awesome…

may be try to Ctrl-A you object !

salutations

Inversion of normals doesn’t cause faces to look like holes. The guy from tut has deleted some faces of small cubes to make them as cups and then inverted normals of the cups to BAKE normalmap properly:

http://a.imageshack.us/img838/1972/82483403.png

Thanks, so this works only with the retopo mesh???, cause I tried to apply the normals on my mesh, but it doesnt work…