Changing XYZ (UCS) Plane

 From:  keebo (KSDIAMOND)
1618.1 
Forgive me if this has been discussed already and if I am not using the correct terminology. By UCS Plane (as in AutoCAD) I mean the default XYZ Plane. Can you change this plane from the default state to a plane that follows an object that is rotated off the plane? Can you create a local UCS? To further explain my question, say I draw an ellipse in the top view mode. I then copy this ellipse and move it up the z axis directly above its original in Side View. I take the Ellipse Copy and rotate it around the X axis so now the plane of the Ellipse Copy is cutting diagonally across XY and Z plane. Now it becomes really hard to make a new copy of the Ellipse Copy and/or do any further manipulations to this plane once it is rotated. Is there something I am missing where I can create a local XYZ plane, where the new Z axis would run perpendicular through the plane of the rotated Ellipse Copy? Sketchup and AutoCAD have a tool like this, if I am not making enough sense. If a tool like this exists is there a tutorial that utilizes this?
I'm a newbie, just started this cool program tonight
Cheers