Geodesic Math

[derekamos]

Hi Sliderule,
No one seems to be able to help, but maybe with a bit of programming adaption this info' will help you reconstruct the missing routines. The github reference lists the whole routine.
DA
--[[
//==========================================
// Geodesic calculations
//
// Reference: Geodesic Math and How to Use It
// By: Hugh Kenner
// Second Paperback Edition (2003), p.74-75
// http://www.amazon.com/Geodesic-Math-How-...0520239318
//
// The book was used for reference, so if you want to check the math,
// you can plug in various numbers to various routines and see if you get
// the same numbers in the book.
//
// In general, there are enough routines here to implement the various
// pieces necessary to make geodesic objects.
// https://github.com/Spiritdude/OpenJSCAD....esic.jscad
//==========================================
--]]

function poly_sum_interior_angles(sides) = (sides-2)*180;
function poly_single_interior_angle(pq) = poly_sum_interior_angles(pq[0])/pq[0];

-- Given a set of coordinates, return the frequency
-- Simply calculated by adding up the values of the coordinates
function geo_freq(xyz) = xyz[0]+xyz[1]+xyz[2];

-- Convert between the 2D coordinates of vertices on the face triangle
-- to the 3D vertices needed to calculate spherical coordinates
function geo_tri2_tri3(xyf) = [xyf[1], xyf[0]-xyf[1], xyf[2]-xyf[0]];

-- Given coordinates for a vertex on the octahedron face
-- return the spherical coordinates for the vertex
-- class 1, method 1
function octa_class1(c) = sph(
atan(safediv(c[0], c[1])),
atan(sqrt(c[0]*c[0]+c[1]*c[1])/c[2]),
1
);

function octa_class2(c) = sph(
atan(c[0]/c[1]),
atan( sqrt( 2*(c[0]*c[0]+c[1]*c[1])) /c[2]),
1
);

function icosa_class1(c) = octa_class1(
[
c[0]*sin(72),
c[1]+c[0]*cos(72),
geo_freq(c)/2+c[2]/Cphi
]);

function icosa_class2(c) = sph(
atan([c0]/c[1]),
atan(sqrt(c[0]*c[0]+c[1]*c[1]))/cos(36)*c[2],
1
);

function tetra_class1(c) = octa_class1(
[
sqrt(3*c[0]),
2*c[1]-c[0],
(3*c[2]-c[0]-c[1])/sqrt(2)
]);

function class1_icosa_chord_factor(v1, v2, freq) = sph_dist(
icosa_class1(geo_tri2_tri3( [v1[0], v1[1], freq])),
icosa_class1(geo_tri2_tri3( [v2[0], v2[1], freq]))
);