Extrude 90°? Noob.

Can I use the extrude tool in such a way to make it extrude only 90° (square to) from its origin. Example, I have a plane and want to use extrude so that the extruded plane remains parallel to the original. I am aware of the ability to extrude along the XYZ axis, but the plane I want to extrude is not on any of these.

Eh?

you can lock to the local plan, either using the widget thing, or hitting x-x/y-y/z-z (twice) for a local axis instead of the world axis. You can also create custom Transform Orientations (in the 3D view menu, select “View” -> “Transform Orientations”). Then add a new one based on the currently selected object. Play with it /visit the wiki to learn more.

Hope that helps.