It is more desirable to start with a suitable initial shape and make incremental changes with a graphical editing program. The starting shapes could be simple geometrical elements such as spheres, cubes, or cylinders, or they could be drawn from a library of previously modeled parts as are now being sold on CD ROMs by various companies. Interesting shapes can also be captured from existing physical models with machinery costing several ten thousands of dollars. Typically a moving swath of laser light illuminates the model, while one or more light detectors catch the reflected light and determine the 3D positions of the targeted points in space. Shape Modification by Interactive Editing To many artists, the act of creating a sculpture may be as important as the pleasure of regarding the final piece.
Computers can give similar pleasures related to the power of interactive creation.
While one cannot yet feel the emerging forms, one can nevertheless change their shapes interactively. With suitable interactive editing software, a surface can be modified locally by moving vertices with some pointing device, such as a mouse or a 3D wand. We can glue on new features, or blend or fuse different shapes together. The use of such editing software is at least two-fold. First, the computer can be used as a virtual prototyping tool.