Move to the 3rd dimension with AutoCAD 2007... it's easier than you might think!
You can create a 3D solid box just like creating a 2D rectangle with height!
Even after you create the box, you can easily edit it using grips. The triangular grips enable you to stretch the box from any of its six sides and the square corner grips enable you to stretch the corners of the box to edit two sides at once! There is also a square center grip so you can easily move the box without changing its shape!
In addition to using grips to edit a box, you can edit its length, width, and height using the Geometry pane of the Properties window!