| 摘要 |
Methods and apparatus for interactively rotating three-dimensional (3D) objects using multitouch gestures. To perform a roll gesture, multiple touch points are detected on a multitouch-enabled device. The touch points are associated with, or select, a 3D object displayed on the device. The centroid of the touch points is computed, and motion of the centroid, resulting from motion of the touch points, is tracked. When motion of the centroid is detected, a displacement is obtained, and the displacement is mapped to a rotation transformation. The 3D object may then be rotated according to the rotation transformation, and a 2D projection of the rotated 3D object is displayed. If the number of touch points changes, rotation may be reset without rotating the object. Alternatively, displacement from the previous centroid to the new centroid is determined and the object is rotated accordingly.
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