Tesselated icosahedron

The description above has assumed that the property that is stored at the vertices of the tessellated icosahedron describing a molecule is either the minimal or the radial distance to the molecular surface. However, it is equally possible to store at each vertex any sort of property that can be calculated for that point in 3D space, such as the molecular electrostatic potential. Thus SPERM, like atom-mapping, allows local, property-based 3D similarity searching. 

Figure 14 Tessellated icosahedron of the kind applied to define the position of sphere surface points used in SPERM gnomonic projection calculations. ...

Figure 5 Stereo view of a tessellated icosahedron. Red spheres are the vertices of the icosahedron, the gray spheres are the centers of the faces (dodecahedron)...

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