| 摘要 |
PURPOSE:To enable a sculptured surface to be handled in stereographic shape including a rational curve by deciding continuity at a boundary, and generating the sculptured surface by generating the internal control point of a plane from a found connection condition. CONSTITUTION:The sculptured surface can be generated with a deciding part 1 which decides the continuity of the plane whose boundary is enclosed with the rational curve at the boundary from a boundary curve and a curve connected to each boundary curve, and a condition setting part 2 which finds the connection condition at the boundary from the continuity found at the deciding part 1, and a generation part 3 which generates the internal control point of the plane from the connection condition found at the condition setting part 2. In the sculptured surface generating system, a double tertiary rational boundary Gregory patch is used as the expressive quation of a curved surface. Thereby, it is possible to generate the sculptured surface on the plane having the boundary curve including three or more rational curves as keeping the continuity.
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