| 摘要 |
<p>2-dimensional image data is produced from multidimensional image data. The 2-dimensional image data represents a view of the 3-dimensional model from a particular view point. In the 3-dimensional model, data is stored relating to the position of vertices, therefore, for a particular view point it is not obvious as to whether a polygon is forward facing or back facing. Vectors defining the polygon edges are processed to determine whether the polygon is forward facing or back facing. Thus, by processing the vectors defining the polygon it is not necessary to transform normal vectors and a computational saving is made. Further computational savings may be made if vector processing to determine the orientation of the polygon is also required for other processes, such as scan conversion to coloured pixels. <IMAGE></p> |
