M
mikeonenine@web.de
Sun, Aug 27, 2023 12:52 AM
It needs tidying up, but it ought to work as it is. Subtracting the Hirth shape from the end of a shaft is probably preferable to adding it, as it saves having to round the circumference of the polyhedron by intersecting it with a cylinder.
A bit of complexity helped, but more than 3 doesn’t help more.
What have I overlooked?
$vpr=[-35,-45,0];
// Hirth coupling
module Hirth()
{
for(i = [1 : 16])
rotate(i * 360/16)
polyhedron( convexity=5,
points = [
[0,0,2],
[11, PI*11.145/16, -PI*11.145/16/2*tan(60)+2],
[11, -PI*11.145/16, -PI*11.145/16/2*tan(60)+2],
[11, 0, PI*11.145/16/2*tan(60)+2],
[0,0,0]
],
faces = [
[1,2,3],
[0,1,2],
[3,2,0],
[3,0,1],
[4,1,2],
[4,0,2],
[4,0,1],
]);
}
// Shaft 1
translate([0,0,10])
difference()
{
translate([0,0,25])
cylinder(r=10, h=50, center=true);
rotate([0,0,360/64])
Hirth();
}
// Shaft 2
translate([0,0,-10])
rotate([0,180,0])
difference()
{
translate([0,0,25])
cylinder(r=10, h=50, center=true);
rotate([0,0,360/64])
Hirth();
}
It needs tidying up, but it ought to work as it is. Subtracting the Hirth shape from the end of a shaft is probably preferable to adding it, as it saves having to round the circumference of the polyhedron by intersecting it with a cylinder.
A bit of complexity helped, but more than 3 doesn’t help more.
What have I overlooked?
$vpr=\[-35,-45,0\];
// Hirth coupling
module Hirth()
{
for(i = \[1 : 16\])
rotate(i \* 360/16)
polyhedron( convexity=5,
points = \[
\[0,0,2\],
\[11, PI\*11.145/16, -PI\*11.145/16/2\*tan(60)+2\],
\[11, -PI\*11.145/16, -PI\*11.145/16/2\*tan(60)+2\],
\[11, 0, PI\*11.145/16/2\*tan(60)+2\],
\[0,0,0\]
\],
faces = \[
\[1,2,3\],
\[0,1,2\],
\[3,2,0\],
\[3,0,1\],
\[4,1,2\],
\[4,0,2\],
\[4,0,1\],
\]);
}
// Shaft 1
translate(\[0,0,10\])
difference()
{
translate(\[0,0,25\])
cylinder(r=10, h=50, center=true);
rotate(\[0,0,360/64\])
Hirth();
}
// Shaft 2
translate(\[0,0,-10\])
rotate(\[0,180,0\])
difference()
{
translate(\[0,0,25\])
cylinder(r=10, h=50, center=true);
rotate(\[0,0,360/64\])
Hirth();
}
M
mikeonenine@web.de
Sun, Aug 27, 2023 4:49 AM
Found the culprit!
Following consultation of the Manual, I discovered a hidden internal face. Getting rid of that fixed it:
$fn=100;
// F12 to check faces
$vpr=[-35,-45,0]; // Isometric view
// Hirth coupling
module Hirth()
{
for(i = [1 : 16])
rotate(i * 360/16)
polyhedron( convexity=3,
points = [
[0,0,2],
[11, PI*11.145/16, 0],
[11, -PI*11.145/16, 0],
[11, 0, PI*11.145/16*tan(60)],
[0,0,0]
],
faces = [
[1,2,3],
[3,2,0],
[3,0,1],
[4,2,1],
[4,0,2],
[4,1,0],
]);
}
// Shaft 1
translate([0,0,25-1])
difference()
{
cylinder(r=10, h=50, center=true);
cylinder(r=4, h=51, center=true);
translate([0,0,-25-0.001])
rotate([0,0,360/64])
Hirth();
}
// Shaft 2
translate([0,0,-25+1])
rotate([0,180,0])
difference()
{
cylinder(r=10, h=50, center=true);
cylinder(r=4, h=51, center=true);
translate([0,0,-25-0.001])
rotate([0,0,360/64])
Hirth();
}
Apologies to anyone who has been scratching their head on my behalf in the meantime!
Found the culprit!
Following consultation of the Manual, I discovered a hidden internal face. Getting rid of that fixed it:
$fn=100;
// F12 to check faces
$vpr=\[-35,-45,0\]; // Isometric view
// Hirth coupling
module Hirth()
{
for(i = \[1 : 16\])
rotate(i \* 360/16)
polyhedron( convexity=3,
points = \[
\[0,0,2\],
\[11, PI\*11.145/16, 0\],
\[11, -PI\*11.145/16, 0\],
\[11, 0, PI\*11.145/16\*tan(60)\],
\[0,0,0\]
\],
faces = \[
\[1,2,3\],
\[3,2,0\],
\[3,0,1\],
\[4,2,1\],
\[4,0,2\],
\[4,1,0\],
\]);
}
// Shaft 1
translate(\[0,0,25-1\])
difference()
{
cylinder(r=10, h=50, center=true);
cylinder(r=4, h=51, center=true);
translate(\[0,0,-25-0.001\])
rotate(\[0,0,360/64\])
Hirth();
}
// Shaft 2
translate(\[0,0,-25+1\])
rotate(\[0,180,0\])
difference()
{
cylinder(r=10, h=50, center=true);
cylinder(r=4, h=51, center=true);
translate(\[0,0,-25-0.001\])
rotate(\[0,0,360/64\])
Hirth();
}
Apologies to anyone who has been scratching their head on my behalf in the meantime!
