Descriptions and Examples for the POV-Ray Raytracer by Friedrich A. Lohmüller
Elementary Geometry for Raytracing
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Regular Dodecahedron Some useful geometrical facts


In the following we write for the square root of a number the expression "sqrt(ZAHL)"
conforming to the syntax used in POV-Ray.


Dimensions of a regular dodecahedron
Length of an edge of the dodecahedron: a.
The radius of circumsphere:
R = a / 4 * sqrt( 3 ) * ( 1 + sqrt(5) ) ;
The radius of edgesphere (tangent to edges):
Re = a / 4 * ( 3 + sqrt(5) ) ;

The radius of the insphere:
Ri = a / 2 * sqrt( ( 25 + 10*sqrt(5))/10 );

The angle between two faces: ~116.57°
Face_Angle =
degrees( acos(-1/5*sqrt(5)) );


The angle between two edges: ~ ~121.72°
Face_Edge_Angle =
degrees( acos( -sqrt( (5-sqrt(5))/10 ) ) );


        Flolding of a regular dodecahedron
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© Friedrich A. Lohmüller, 2011
www.f-lohmueller.de