We present an interactive pen-based computer program for designing 3D objects through direct sketching. The proposed techniques are tailored toward the creation of free-form curves and surfaces, and are therefore particulary useful for styling design purposes. In our approach, the design process consists of two main steps. In the first step, the user designs a wireframe model by sketching its constituent curves in 3D. Using purely sketch-based operations, the initial curves can then be modified as desired. In the second step, the user constructs interpolating surfaces on the wireframe to obtain a solid model. Again, through sketch-based operations, the user can modify the initial surfaces, and specify the boundary conditions if necessary. In addition to the main modeling operations, a gesture-based command interface allows many of the frequently used commands to be input through pen strokes. The utility of our system is demonstrated with various examples.
Levent Burak Kara, Kenji Shimada. (2006). Construction and Modification of 3D Geometry Using a Sketch-based Interface. Eurographics Workshop on Sketch-Based Interfaces and Modeling 2006.