Autodesk Labs has just released named Interactive Terrain Shaping for AutoCAD Civil 3D 2012.

You will be able to interactively create and visually explore new conceptual grading plans. To me it appears the direct modeling paradigm or dynamic model interaction has come to civil design.

We are introducing direct 3D model interaction in this new approach to allow users to optimize their designs in-canvas with intuitive interaction and dynamic feedback. We are also introducing design by flow grade in this approach. The flow grade is measured along the gradient of the surface, and is more suitable for designing parking lots and landfills. Flow grade allows the specification of maximum allowable grade which may be dictated by soil quality, design standards and ADA guidelines. Designing by flow grade and direction allows more control on drainage pattern.

Check out the Interactive Terrain Shaping technology preview and the videos.