Fig. 5
From: Precise parallel volumetric comparison of molecular surfaces and electrostatic isopotentials
a Spindle. b Formation of a spindle (gray) in a simple molecular surface defined on two atoms (red) and a solvent sphere (yellow). The perpendicular projection of the center of the solvent sphere onto the interatomic axis defines the center point. c “broken” spindle. d Torus defining some characteristics of a spindle, including center point (black dot, center), perpendicular vector (vertical arrow), major radius (arrow from center point to horizontal ellipse), minor radius (diagonal arrow from horizontal ellipse to torus surface. e Cylinder (light blue with black outline)