UCS/Extruding

My general method of extroding is; PE, The Polyline Edit command does not include an extrude option. To extrude an object there has to be a face and a path. The path is usually a polyline because it is easier to make a 3D path out of a polyline. You are not extruding the polyline, but the 3D face. You should open the help, the F1 key, and then search the index for extrude. There are quite a few entries relating to the extrude command that should explain very well how this is accomplished.
All that being said I would have created the polyline that represents the path of the duct, then at one end line up the UCS to the angle of the face, usually 90 degrees to the end of the polyline, then extrude that shape along the path of the polyline.

Hi, Thanks for the tip... I use PE (Pedit) because i draw with regular lines then convert to poly. the shape is a piece of steel plate. So i draw it with regular lines in the plane it is actually in.... many pieces of plate, all in different planes, making up a chute. Once it is drawn and all fits together i need to extrude the 'plates' to give them the thickness of whatever steel they are made out of.
So i go PE, Multiple, select all the lines that represent one plate, then choose yes when asked if i want to convert to polylines. Then I Join. After this i can extrude. The trouble that i have is that i cant convert the lines to polylines because they are not on any planes of the UCS, and i cant align the UCS to the plate because it is such an odd shape... not square in any way, and not alligned with any part of the normal UCS; it is out of alignment on X,Y and Z. By trying to align the UCS to the object I can usually get it flat on only one plane.
Will have a look at the extrude command again, also will try to lookup 3D polylines, maybe there is an option there? Spent most of the afternoon unproductively looking through the help section on the UCS, and different ways of aligning... I did finally work out how the positive/negative #D rotation works though which will reduce the number of times I scream in future ;-)
Thanks! Shaun

Neglected to mention the critical data!
Autocad 2002
We have one machine which had 2007 on it, but was upgraded(?) to 2008 which i havent had a chance to get a look at yet. Budget doesnt look like it will cover a second license either :-(
Shaun