When you choose "TAKE OFF" from the Design Commands it does "STEEL TAKE OFF". You will have to go into the editor and change it to "ALUMINUM TAKE OFF". Just another one of the many user friendly features provided by our friends at Bentley.

Thank you so much dozer.

It works the way you mentioned.

Just thought I'd add another way you can add the ALUMINIUM TAKE OFF command using the graphical interface rather than menus.
Click on the 'Design' Page Control tab on the left of the screen. That displays the various methods avaialble as sub-tabs, the default being the top which is 'Steel'. The forth tab is 'Aluminum'. If you click on that to add the paramaters and commands for the alumminum design, then the dialog on the right will provide aluminium design commands. Click on the 'Commands' button , seelct 'Take Off' and click Add (or assign if you have pre-selected the members you wish to measure). You should find that the command ALUMINUM MEMBER TAKE OFF (member list) will be added to your file when you display it in the editor.