As Jenea mentioned, several Cooper designers love their tablet PCs, and many love to sketch in OneNote. Recently, Alan sent this video around; obviously, sketching has been taken to the next level. The tool is called ILoveSketch, by Seok-Hyung Bae, Ravin Balakrishnan, and Karan Singh, and it looks kind of mind-blowing.
The creators describe their system as:
A 3D curve sketching system that captures some of the affordances of pen and paper for professional designers, allowing them to iterate directly on concept 3D curve models. The system coherently integrates existing techniques of sketch-based interaction with a number of novel and enhanced features. Novel contributions of the system include automatic view rotation to improve curve sketchability, an axis widget for sketch surface selection, and implicitly inferred changes between sketching techniques. We also improve on a number of existing ideas such as a virtual sketchbook, simplified 2D and 3D view navigation, multi-stroke NURBS curve creation, and a cohesive gesture vocabulary.
It's hard to see exactly what's going on, interaction-wise, but there are certainly some new and unique interaction patterns in the demo, and a potentially steep learning curve, but nothing that seems counter-intuitive. It allows people to effectively sketch 3D objects without perhaps the extensive skill of perspective drawing. The replicated sketching functionality would also ensure perfect symmetry of an object like that demonstrated with the plane. Most of all, it looks like lots of fun.
(Thanks to Dr. Marty for the link.)