Three-dimensional data sets surface rendering

The new set of varied DF found in the previous section can be studied in the same way as the well-known eDF maps are represented since the first plots used in Quantum Chemistry [53a)]. Here an alternative point of view, similar as the one used by Mezey [9a)], will be chosen. Three-dimensional maps of isodensity surfaces can be generated with available computational techniques [84]. This corresponds to follow several steps, some of them so trivial that appear to be irrelevant in a study as the present. The representation process starts with the evaluation of DF grids, enveloping the molecular co-ordinates, which can origin wireframe structures related with the isodensity values. After that, they can be rendered and rotated in space as virtual objects, until some adequate point of view is found. Finally, the chosen object snapshot can be manipulated, represented on a screen and, if necessary, printed into a paper surface. The processing detail, the computational techniques and the required programs and data are briefly commented in Appendix E. All the necessary items are available to the interested reader and permit to generate surfaces of his own [93-96]. 

Three-dimensional medical images of CT and MR data sets can be generated with a variety of computer algorithms. The three most commonly used techniques are shaded surface display (SSD), maximum intensity projection (MIP) and 3D volume rendering (Calhoun et al. 1999). 

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