Brian Haines has created this very cool video, showing in detail as to how the process works. He describes the steps, from the creation of 2D or 3D content with Revit Architectural to the import into Autodesk Quantity Takeoff, and the subsequent data display.
Autodesk® Quantity Takeoff software enables cost estimators to gather design data, high-quality images, and precise information from intelligent design applications such as AutoCAD®, Revit® Architecture, and AutoCAD® Civil 3D®, as well as from “nonintelligent” CAD data and image formats.
Way to go, QTO.
You can view the video here or download it, by right clicking the link and choosing the "Save Target As.." option.