A new modeling interface for the pen-input displays

Sketch interactions based on interpreting multiple pen markings into a 3D shape is easy to design but not to use. First of all, it is difficult for the user to memorize a complete set of pen markings for a certain 3D shape. Secondly, the system will be waiting for the user to complete the sequence of the pen markings, often causing a certain mode error. To address these problems, we present a novel, interaction framework, suitable for interpretations based on single-stroke marking on pen-input display; within this framework 3D shape modeling operations are designed to create appropriate communication protocols. q 2005 Elsevier Ltd. All rights reserved.