Surface design using hand motion with smoothing

We describe elements used in a system to manipulate a polygon-based surface object using a data glove (made by Fifth Dimension Inc.). A direct-manipul ation method is used that allows for placing new displacements on previous ones. Good results are obtained for manipulation at any incidence angle to the surface by using a new linear transformation on the selected vertices, in order to properly calculate their displacement magnitudes. The design of the manipulation system emphasizes intuitiveness and speed. A method for smoothing selected portions of the object is also presented. T he smoothing tool does not change regions of the surface where vertex coord inates may be expressed as a second-order implicit function i.e, the method has quadratic precision. It operates by finding a least-squares fit, follo wed by a relaxation phase where vertices are moved near the surface approxi mation. The smoother operates on a set of disjoint points in space, no know ledge of connectivity is required by the surface smoother. (C) 2001 Elsevie r Science Ltd. All rights reserved.