| 摘要 |
The present invention relates to a system of interactive navigation of a tool relative to three-dimensional volumetric data. The tool may be a camera or a brush and the volume data may be points, curves, iso-surfaces, geometric surfaces or combinations thereof. Moreover, the volume data may be explicitly or implicitly created. In the case of a camera and a surface, a surface of the model is viewed from an initial view point with an initial view direction. A two-dimensional vector, as by moving a mouse, is used to translate the initial view point to a next view point in a plane normal to the view direction and intersecting the initial view point. A point of the surface that is closest to the next view point may then be found, and the next direction of the view is set to the direction from the next position of the view point to the closest surface point. The closest point is found by casting rays from the next view point. The next view direction may be set to the direction of the ray corresponding to the point with the smallest distance. The next view point may be further translated toward or away from the closest surface point, along the newly set next view direction, to a location that is a same distance from the surface as the initial view point.
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