| 摘要 |
PURPOSE:To display a wire frame to distinguish the front and back sides of a curved surface and a plane with the small amount of data by providing a means to interpolate a direction vector and to determine it and a means to determine the display method of an arbitrary point from the direction vector and a sighting direction vector. CONSTITUTION:To respective plural points on the border line of the curved surface, as the direction vectors of those points, a normal vector is applied at the point of the curved surface and when the curved surface is displayed, only the border line is displayed. As a border line display method, the direction vector at the arbitrary point on the border line is calculated from the plural direction vectors applied to the border line by interpolation and an inner product value between the glance direction vector and the interpolating direction vector is calculated. Then, the arbitrary point of the border line is displayed by a display method corresponding to the inner product value applied in advance. Thus, it is not necessary to apply the direction vectors concerning all the points of a curve as display data in advance, the amount of the display data can be reduced and the distinguishment for the front and back sides of the curve is always assured corresponding to slighting direction. |
