Extruding troubles

[Martin Mcghee]

It looks like you haven’t selected the back planes so those weird bars are the faces being generated by the extrusion of the front planes only.
for the result shown in the tutorial you will have to extrude the entire loop inwards, including the backwards facing planes.

You could select all of the loop by having the ‘Use polygon tool’ active and the picking the menu item:

Selection > Loop selection

and picking the middle loop as in the image.

or you could select the planes by having ‘Only Select Visible Elements’ unticked in your default selection tool and picking ‘through’ the front planes.

hope this helps a little, if you’re still not sure, just ask,

good luck,

moxomule.