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NopSCADlib
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Sweep can now cope with the start having colinear points.

This commit is contained in:
Chris Palmer 2020-11-04 19:56:51 +00:00
parent 7b126f9792
commit 1658f6f0b4
1 changed files with 10 additions and 3 deletions
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13
utils/sweep.scad
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@ -34,14 +34,22 @@ function transpose3(m) = [ [m[0].x, m[1].x, m[2].x],
[m[0].y, m[1].y, m[2].y],
[m[0].z, m[1].z, m[2].z] ];
//
// Find the first non-colinear point
//
tiny = 0.00001;
function find_curve(tangents, i = 1) =
i >= len(tangents) - 1 || norm(cross(tangents[0], tangents[i] - tangents[0])) > tiny ? i
: find_curve(tangents, i + 1);
//
// Frenet-Serret frame
//
function fs_frame(tangents) =
let(tangent = tangents[0],
normal = tangents[1] - tangents[0],
i = find_curve(tangents),
normal = tangents[i] - tangents[0],
binormal = cross(tangent, normal),
z = unit(tangent),
x = assert(norm(binormal) > 0.00001, "first three points are colinear") unit(binormal),
x = assert(norm(binormal) > tiny, "all points are colinear") unit(binormal),
y = unit(cross(z, x))
) [[x.x, y.x, z.x],
[x.y, y.y, z.y],
@ -70,7 +78,6 @@ function orientate(p, r) =
[x.y, y.y, z.y],
[x.z, y.z, z.z],
[p.x, p.y, p.z]];
//
// Rotate around z
//