| 摘要 |
A method for generating a three-dimensional computer graphics image; in particular, a method of generating an image of a clipped object. The object is rendered using a plurality of three-dimensional geometric shapes. In the present embodiment, the geometric shapes are tetrahedrons. One or more of the tetrahedrons is intersected by a planar surface, thereby dividing the tetrahedron into a first subvolume and a second subvolume. A new vertex is created at each intersection of the planar surface with an edge of a tetrahedron. Each vertex of the tetrahedron is categorized as lying on one side of the planar surface or the other. Each vertex lying on the side of the planar surface that is in the first subvolume is placed into a first group. The first group is used to select a set of instructions. In one embodiment, each vertex of the geometric shape is uniquely identified. Thus, the first group of vertices contains a unique combination of vertex identifiers that allow a particular set of instructions pertaining to that combination to be selected. In one embodiment, the set of instructions are contained in a lookup table. The vertices in the first group and each new vertex are connected according to the set of instructions to form three-dimensional tetrahedrons rendering the first subvolume.
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