| 摘要 |
A graphic display method and apparatus to improve the ease of operations by enabling a more direct operation for rotating an object in a three-dimensional space, and to make it possible to change the attitude of the object over a wide range of viewing points is provided. A semitransparent spherical surface 22 having as its centre O a fixed point in an object 21 being displayed on a screen of a tablet is generated so as to enclose the object 21. Then, three degrees of freedom for orientation are determined by pen-manipulation on the spherical surface 22. That is, a plurality of points (P0-P3) on the spherical surface 22 are specified in a predetermined order. For example, a rotation axis OP1 is specified by specification of points P0 and P1, and then a rotation angle alpha about this axis OP1 is specified by the specification of points P2 and P3. Then, calculations for rotating the object 2 to the specified orientation are performed, and the rotated object 21 is displayed. According to this procedure, the object 21 in the three-dimensional space can be rotated to an arbitrary orientation in a desired manner. <IMAGE> |
