Hi,

Guest

L

larry

Fri, Sep 20, 2024 3:26 AM

Doesn't work for me.

On Fri, 2024-09-20 at 01:07 +0000, Caddiy via Discuss wrote:

Does this work for you?$fn=100;$vpr=[ 60, 0, 315 ];

$vpt=[ 0, 0, 0 ];

$vpd=80;

a=60; // Base angle

r=12; // Radius

n=16; // Number of splines

module facespline()

{

difference()

{

intersection()

{

for(i = [1 : n])

rotate(i * 360/n)

polyhedron(

points = [

[0, 0, PI*r/2/n*tan(a)],

[r, r*tan(360/2/n), 0],
[r, -r*tan(360/2/n), 0],

[r, 0, PI

[0, 0, 0]

],

faces = [

[1,2,3],

[3,2,0],

[3,0,1],

[0,2,4],

[0,4,1],

[1,4,2]

]);

cylinder(r=r, h=PI

}

// Hole

translate([0,0,-1])

cylinder(r=6, h=5);

}}

// Face spline coupling

{

translate([0, 0, -3])

facespline();

translate([0, 0, 3])

rotate([0, 180, 360/2/n])

facespline();

}

OpenSCAD mailing list

To unsubscribe send an email to discuss-leave@lists.openscad.org

Doesn't work for me.
On Fri, 2024-09-20 at 01:07 +0000, Caddiy via Discuss wrote:
> Does this work for you?$fn=100;$vpr=[ 60, 0, 315 ];
> $vpt=[ 0, 0, 0 ];
> $vpd=80;
> a=60; // Base angle
> r=12; // Radius
> n=16; // Number of splines
> module facespline()
> {
> difference()
> {
> intersection()
> {
> for(i = [1 : n])
> rotate(i * 360/n)
> polyhedron(
> points = [
> [0, 0, PI*r/2/n*tan(a)],
> [r, r*tan(360/2/n), 0],
> [r, -r*tan(360/2/n), 0],
> [r, 0, PI*r/n*tan(a)],
> [0, 0, 0]
> ],
> faces = [
> [1,2,3],
> [3,2,0],
> [3,0,1],
> [0,2,4],
> [0,4,1],
> [1,4,2]
> ]);
> cylinder(r=r, h=PI*r/16*tan(a)+1);
> }
> // Hole
> translate([0,0,-1])
> cylinder(r=6, h=5);
> }}
> // Face spline coupling
> {
> translate([0, 0, -3])
> facespline();
> translate([0, 0, 3])
> rotate([0, 180, 360/2/n])
> facespline();
> }
>
> _______________________________________________
> OpenSCAD mailing list
> To unsubscribe send an email to discuss-leave@lists.openscad.org

K

Ken

Fri, Sep 20, 2024 3:36 AM

Sorry Mike, same result as before.

On 2024-09-20 11:07, Caddiy via Discuss wrote:

```
Does this work for you?
|$fn=100;|
```

|$vpr=[ 60, 0, 315 ];|

|$vpt=[ 0, 0, 0 ];|

|$vpd=80;|

|a=60; // Base angle|

|r=12; // Radius|

|n=16; // Number of splines|

|module facespline()|

|{|

|difference()|

|{|

|intersection()|

|{|

|for(i = [1 : n])|

|rotate(i * 360/n)|

|polyhedron(|

|points = [|

|[0, 0, PI*r/2/n*tan(a)],|

|[r, r*tan(360/2/n), 0],|

|[r, -r*tan(360/2/n), 0],|

|[r, 0, PI*r/n*tan(a)],|

|[0, 0, 0]|

|],|

|faces = [|

|[1,2,3],|

|[3,2,0],|

|[3,0,1],|

|[0,2,4], |

|[0,4,1], |

|[1,4,2] |

|]);|

|cylinder(r=r, h=PI*r/16*tan(a)+1);|

|}|

|// Hole|

|translate([0,0,-1])|

|cylinder(r=6, h=5);|

|}}|

|// Face spline coupling|

|{|

|translate([0, 0, -3])|

|facespline();|

|translate([0, 0, 3])|

|rotate([0, 180, 360/2/n])|

|facespline();|

|}|

OpenSCAD mailing list

To unsubscribe send an email todiscuss-leave@lists.openscad.org

Cheers, Ken

bats059@gmail.com

https://vk7krj.com

https://vk7krj.com/running.html

A baby can be defined as an ego with a noise at one end and a smell at the other.

Your job as parents is to teach them to control all three.

My job as a grandad is to tell you how you are doing it all wrong!

Sorry Mike, same result as before.
On 2024-09-20 11:07, Caddiy via Discuss wrote:
>
>
> Does this work for you?
>
>
> |$fn=100;|
>
> |$vpr=[ 60, 0, 315 ];|
>
> |$vpt=[ 0, 0, 0 ];|
>
> |$vpd=80;|
>
> |a=60; // Base angle|
>
> |r=12; // Radius|
>
> |n=16; // Number of splines|
>
> |module facespline()|
>
> |{|
>
> |difference()|
>
> |{|
>
> |intersection()|
>
> |{|
>
> |for(i = [1 : n])|
>
> |rotate(i * 360/n)|
>
> |polyhedron(|
>
> |points = [|
>
> |[0, 0, PI*r/2/n*tan(a)],|
>
> |[r, r*tan(360/2/n), 0],|
>
> |[r, -r*tan(360/2/n), 0],|
>
> |[r, 0, PI*r/n*tan(a)],|
>
> |[0, 0, 0]|
>
> |],|
>
> |faces = [|
>
> |[1,2,3],|
>
> |[3,2,0],|
>
> |[3,0,1],|
>
> |[0,2,4], |
>
> |[0,4,1], |
>
> |[1,4,2] |
>
> |]);|
>
> |cylinder(r=r, h=PI*r/16*tan(a)+1);|
>
> |}|
>
> |// Hole|
>
> |translate([0,0,-1])|
>
> |cylinder(r=6, h=5);|
>
> |}}|
>
> |// Face spline coupling|
>
> |{|
>
> |translate([0, 0, -3])|
>
> |facespline();|
>
> |translate([0, 0, 3])|
>
> |rotate([0, 180, 360/2/n])|
>
> |facespline();|
>
> |}|
>
>
>
> _______________________________________________
> OpenSCAD mailing list
> To unsubscribe send an email todiscuss-leave@lists.openscad.org
--
Cheers, Ken
bats059@gmail.com
https://vk7krj.com
https://vk7krj.com/running.html
----------------------------------------
A baby can be defined as an ego with a noise at one end and a smell at the other.
Your job as parents is to teach them to control all three.
My job as a grandad is to tell you how you are doing it all wrong!

MM

Michael Marx (spintel)

Fri, Sep 20, 2024 6:21 AM

I think you guys not seeing it may have Lazy Union enable.

Problem is the intersection() of the for(), as each arm of the for() doesn't overlap, so intersection() returns empty.

With Lazy union disabled (or not in 2021.01) the for() does a union().

To fix, stick union() in front of the for().

From: Ken via Discuss [mailto:discuss@lists.openscad.org]

Sent: Fri, 20 Sep 2024 13:36

To: discuss@lists.openscad.org

Cc: Ken

Subject: [OpenSCAD] Re: Face spline

Sorry Mike, same result as before.

On 2024-09-20 11:07, Caddiy via Discuss wrote:

Does this work for you?

$fn=100;

$vpr=[ 60, 0, 315 ];

$vpt=[ 0, 0, 0 ];

$vpd=80;

a=60; // Base angle

r=12; // Radius

n=16; // Number of splines

module facespline()

{

difference()

{

intersection()

{

for(i = [1 : n])

rotate(i * 360/n)

polyhedron(

points = [

[0, 0, PI*r/2/n*tan(a)],

[r, r*tan(360/2/n), 0],

[r, -r*tan(360/2/n), 0],

[r, 0, PI*r/n*tan(a)],

[0, 0, 0]

],

faces = [

[1,2,3],

[3,2,0],

[3,0,1],

[0,2,4],

[0,4,1],

[1,4,2]

]);

cylinder(r=r, h=PI*r/16*tan(a)+1);

}

// Hole

translate([0,0,-1])

cylinder(r=6, h=5);

}}

// Face spline coupling

{

translate([0, 0, -3])

facespline();

translate([0, 0, 3])

rotate([0, 180, 360/2/n])

facespline();

}

OpenSCAD mailing list

To unsubscribe send an email to discuss-leave@lists.openscad.org

Cheers, Ken

bats059@gmail.com

https://vk7krj.com

https://vk7krj.com/running.html

A baby can be defined as an ego with a noise at one end and a smell at the other.

Your job as parents is to teach them to control all three.

My job as a grandad is to tell you how you are doing it all wrong!

I think you guys not seeing it may have Lazy Union enable.
Problem is the intersection() of the for(), as each arm of the for() doesn't overlap, so intersection() returns empty.
With Lazy union disabled (or not in 2021.01) the for() does a union().
To fix, stick union() in front of the for().
_____
From: Ken via Discuss [mailto:discuss@lists.openscad.org]
Sent: Fri, 20 Sep 2024 13:36
To: discuss@lists.openscad.org
Cc: Ken
Subject: [OpenSCAD] Re: Face spline
Sorry Mike, same result as before.
On 2024-09-20 11:07, Caddiy via Discuss wrote:
Does this work for you?
$fn=100;
$vpr=[ 60, 0, 315 ];
$vpt=[ 0, 0, 0 ];
$vpd=80;
a=60; // Base angle
r=12; // Radius
n=16; // Number of splines
module facespline()
{
difference()
{
intersection()
{
for(i = [1 : n])
rotate(i * 360/n)
polyhedron(
points = [
[0, 0, PI*r/2/n*tan(a)],
[r, r*tan(360/2/n), 0],
[r, -r*tan(360/2/n), 0],
[r, 0, PI*r/n*tan(a)],
[0, 0, 0]
],
faces = [
[1,2,3],
[3,2,0],
[3,0,1],
[0,2,4],
[0,4,1],
[1,4,2]
]);
cylinder(r=r, h=PI*r/16*tan(a)+1);
}
// Hole
translate([0,0,-1])
cylinder(r=6, h=5);
}}
// Face spline coupling
{
translate([0, 0, -3])
facespline();
translate([0, 0, 3])
rotate([0, 180, 360/2/n])
facespline();
}
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
--
Cheers, Ken
bats059@gmail.com
https://vk7krj.com
https://vk7krj.com/running.html
----------------------------------------
A baby can be defined as an ego with a noise at one end and a smell at the other.
Your job as parents is to teach them to control all three.
My job as a grandad is to tell you how you are doing it all wrong!

K

Ken

Fri, Sep 20, 2024 7:08 AM

Thanks Michael, that fixed it!

On 2024-09-20 16:21, Michael Marx (spintel) via Discuss wrote:

I think you guys not seeing it may have Lazy Union enable.

Problem is the intersection() of the for(), as each arm of the for() doesn't overlap, so intersection() returns empty.

With Lazy union disabled (or not in 2021.01) the for() does a union().

To fix, stick union() in front of the for().

*From:*Ken via Discuss [mailto:discuss@lists.openscad.org]
*Sent:* Fri, 20 Sep 2024 13:36
*To:* discuss@lists.openscad.org
*Cc:* Ken
*Subject:* [OpenSCAD] Re: Face spline

Sorry Mike, same result as before.

On 2024-09-20 11:07, Caddiy via Discuss wrote:

```
*Does this work for you?*
|*$fn=100;*|
```

|$vpr=[ 60, 0, 315 ];|

|$vpt=[ 0, 0, 0 ];|

|$vpd=80;|

|a=60; // Base angle|

|r=12; // Radius|

|n=16; // Number of splines|

|module facespline()|

|{|

|difference()|

|{|

|intersection()|

|{|

|for(i = [1 : n])|

|rotate(i * 360/n)|

|polyhedron(|

|points = [|

|[0, 0, PI*r/2/n*tan(a)],|

|[r, r*tan(360/2/n), 0],|

|[r, -r*tan(360/2/n), 0],|

|[r, 0, PI*r/n*tan(a)],|

|[0, 0, 0]|

|],|

|faces = [|

|[1,2,3],|

|[3,2,0],|

|[3,0,1],|

|[0,2,4], |

|[0,4,1], |

|[1,4,2] |

|]);|

|cylinder(r=r, h=PI*r/16*tan(a)+1);|

|}|

|// Hole|

|translate([0,0,-1])|

|cylinder(r=6, h=5);|

|}}|

|// Face spline coupling|

|{|

|translate([0, 0, -3])|

|facespline();|

|translate([0, 0, 3])|

|rotate([0, 180, 360/2/n])|

|facespline();|

|}|

OpenSCAD mailing list

To unsubscribe send an email to discuss-leave@lists.openscad.org

Cheers, Ken

bats059@gmail.com

https://vk7krj.com

https://vk7krj.com/running.html

A baby can be defined as an ego with a noise at one end and a smell at the other.

Your job as parents is to teach them to control all three.

My job as a grandad is to tell you how you are doing it all wrong!

OpenSCAD mailing list

To unsubscribe send an email todiscuss-leave@lists.openscad.org

Cheers, Ken

bats059@gmail.com

https://vk7krj.com

https://vk7krj.com/running.html

Your job as parents is to teach them to control all three.

My job as a grandad is to tell you how you are doing it all wrong!

Thanks Michael, that fixed it!
On 2024-09-20 16:21, Michael Marx (spintel) via Discuss wrote:
>
> I think you guys not seeing it may have Lazy Union enable.
>
> Problem is the intersection() of the for(), as each arm of the for() doesn't overlap, so intersection() returns empty.
>
> With Lazy union disabled (or not in 2021.01) the for() does a union().
>
> To fix, stick union() in front of the for().
>
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> *From:*Ken via Discuss [mailto:discuss@lists.openscad.org]
> *Sent:* Fri, 20 Sep 2024 13:36
> *To:* discuss@lists.openscad.org
> *Cc:* Ken
> *Subject:* [OpenSCAD] Re: Face spline
>
> Sorry Mike, same result as before.
>
> On 2024-09-20 11:07, Caddiy via Discuss wrote:
>
>>
>> *Does this work for you?*
>>
>>
>> |*$fn=100;*|
>>
>> |$vpr=[ 60, 0, 315 ];|
>>
>> |$vpt=[ 0, 0, 0 ];|
>>
>> |$vpd=80;|
>>
>> |a=60; // Base angle|
>>
>> |r=12; // Radius|
>>
>> |n=16; // Number of splines|
>>
>> |module facespline()|
>>
>> |{|
>>
>> |difference()|
>>
>> |{|
>>
>> |intersection()|
>>
>> |{|
>>
>> |for(i = [1 : n])|
>>
>> |rotate(i * 360/n)|
>>
>> |polyhedron(|
>>
>> |points = [|
>>
>> |[0, 0, PI*r/2/n*tan(a)],|
>>
>> |[r, r*tan(360/2/n), 0],|
>>
>> |[r, -r*tan(360/2/n), 0],|
>>
>> |[r, 0, PI*r/n*tan(a)],|
>>
>> |[0, 0, 0]|
>>
>> |],|
>>
>> |faces = [|
>>
>> |[1,2,3],|
>>
>> |[3,2,0],|
>>
>> |[3,0,1],|
>>
>> |[0,2,4], |
>>
>> |[0,4,1], |
>>
>> |[1,4,2] |
>>
>> |]);|
>>
>> |cylinder(r=r, h=PI*r/16*tan(a)+1);|
>>
>> |}|
>>
>> |// Hole|
>>
>> |translate([0,0,-1])|
>>
>> |cylinder(r=6, h=5);|
>>
>> |}}|
>>
>> |// Face spline coupling|
>>
>> |{|
>>
>> |translate([0, 0, -3])|
>>
>> |facespline();|
>>
>> |translate([0, 0, 3])|
>>
>> |rotate([0, 180, 360/2/n])|
>>
>> |facespline();|
>>
>> |}|
>>
>>
>>
>> _______________________________________________
>> OpenSCAD mailing list
>> To unsubscribe send an email to discuss-leave@lists.openscad.org
>
>
>
> --
> Cheers, Ken
> bats059@gmail.com
> https://vk7krj.com
> https://vk7krj.com/running.html
> ----------------------------------------
> A baby can be defined as an ego with a noise at one end and a smell at the other.
> Your job as parents is to teach them to control all three.
> My job as a grandad is to tell you how you are doing it all wrong!
>
> _______________________________________________
> OpenSCAD mailing list
> To unsubscribe send an email todiscuss-leave@lists.openscad.org
--
Cheers, Ken
bats059@gmail.com
https://vk7krj.com
https://vk7krj.com/running.html
----------------------------------------
A baby can be defined as an ego with a noise at one end and a smell at the other.
Your job as parents is to teach them to control all three.
My job as a grandad is to tell you how you are doing it all wrong!

BC

Bob Carlson

Fri, Sep 20, 2024 4:38 PM

That worked for me too. It’s funny I had to make one of these for a project. My electric golf cart (carries my clubs, not me), has an accessories connector with one of these. Below is the part I made. It’s about 30 mm across. I had to count the blades by hand and measure everything to get it since I had no idea what kind of spline this was. I can’t post the code since I use my own library and BOSL2, but the way I constructed it was to create 1 “fanBlade” and then repeat it 60 times around a circle. Each fanBlade was made by positioning a thin inner shape and a thin out shape, then hull’ing. I’ll be taking a closer look at the posted code to compare the two methods.

￼

On Sep 19, 2024, at 23:21, Michael Marx (spintel) via Discuss discuss@lists.openscad.org wrote:

I think you guys not seeing it may have Lazy Union enable.

Problem is the intersection() of the for(), as each arm of the for() doesn't overlap, so intersection() returns empty.

With Lazy union disabled (or not in 2021.01) the for() does a union().

To fix, stick union() in front of the for().

From: Ken via Discuss [mailto:discuss@lists.openscad.org]

Sent: Fri, 20 Sep 2024 13:36

To: discuss@lists.openscad.org

Cc: Ken

Subject: [OpenSCAD] Re: Face spline

Sorry Mike, same result as before.

On 2024-09-20 11:07, Caddiy via Discuss wrote:

Does this work for you?

$fn=100;

$vpr=[ 60, 0, 315 ];

$vpt=[ 0, 0, 0 ];

$vpd=80;

a=60; // Base angle

r=12; // Radius

n=16; // Number of splines

module facespline()

{

difference()

{

intersection()

{

for(i = [1 : n])

rotate(i * 360/n)

polyhedron(

points = [

[0, 0, PI*r/2/n*tan(a)],

[r, r*tan(360/2/n), 0],

[r, -r*tan(360/2/n), 0],

[r, 0, PI*r/n*tan(a)],

[0, 0, 0]

],

faces = [

[1,2,3],

[3,2,0],

[3,0,1],

[0,2,4],

[0,4,1],

[1,4,2]

]);

cylinder(r=r, h=PI*r/16*tan(a)+1);

}

// Hole

translate([0,0,-1])

cylinder(r=6, h=5);

}}

// Face spline coupling

{

translate([0, 0, -3])

facespline();

translate([0, 0, 3])

rotate([0, 180, 360/2/n])

facespline();

}

OpenSCAD mailing list

To unsubscribe send an email to discuss-leave@lists.openscad.org mailto:discuss-leave@lists.openscad.org

Cheers, Ken

bats059@gmail.com mailto:bats059@gmail.com

https://vk7krj.com https://vk7krj.com/

https://vk7krj.com/running.html

Your job as parents is to teach them to control all three.

My job as a grandad is to tell you how you are doing it all wrong!

OpenSCAD mailing list

To unsubscribe send an email to discuss-leave@lists.openscad.org

That worked for me too. It’s funny I had to make one of these for a project. My electric golf cart (carries my clubs, not me), has an accessories connector with one of these. Below is the part I made. It’s about 30 mm across. I had to count the blades by hand and measure everything to get it since I had no idea what kind of spline this was. I can’t post the code since I use my own library and BOSL2, but the way I constructed it was to create 1 “fanBlade” and then repeat it 60 times around a circle. Each fanBlade was made by positioning a thin inner shape and a thin out shape, then hull’ing. I’ll be taking a closer look at the posted code to compare the two methods.
￼
> On Sep 19, 2024, at 23:21, Michael Marx (spintel) via Discuss <discuss@lists.openscad.org> wrote:
>
> I think you guys not seeing it may have Lazy Union enable.
> Problem is the intersection() of the for(), as each arm of the for() doesn't overlap, so intersection() returns empty.
> With Lazy union disabled (or not in 2021.01) the for() does a union().
>
> To fix, stick union() in front of the for().
>
>
> From: Ken via Discuss [mailto:discuss@lists.openscad.org]
> Sent: Fri, 20 Sep 2024 13:36
> To: discuss@lists.openscad.org
> Cc: Ken
> Subject: [OpenSCAD] Re: Face spline
>
> Sorry Mike, same result as before.
>
>
> On 2024-09-20 11:07, Caddiy via Discuss wrote:
>> Does this work for you?
>>
>> $fn=100;
>>
>> $vpr=[ 60, 0, 315 ];
>>
>> $vpt=[ 0, 0, 0 ];
>>
>> $vpd=80;
>>
>> a=60; // Base angle
>>
>> r=12; // Radius
>>
>> n=16; // Number of splines
>>
>> module facespline()
>>
>> {
>>
>> difference()
>>
>> {
>>
>> intersection()
>>
>> {
>>
>> for(i = [1 : n])
>>
>> rotate(i * 360/n)
>>
>> polyhedron(
>>
>> points = [
>>
>> [0, 0, PI*r/2/n*tan(a)],
>>
>> [r, r*tan(360/2/n), 0],
>>
>> [r, -r*tan(360/2/n), 0],
>>
>> [r, 0, PI*r/n*tan(a)],
>>
>> [0, 0, 0]
>>
>> ],
>>
>> faces = [
>>
>> [1,2,3],
>>
>> [3,2,0],
>>
>> [3,0,1],
>>
>> [0,2,4],
>>
>> [0,4,1],
>>
>> [1,4,2]
>>
>> ]);
>>
>> cylinder(r=r, h=PI*r/16*tan(a)+1);
>>
>> }
>>
>> // Hole
>>
>> translate([0,0,-1])
>>
>> cylinder(r=6, h=5);
>>
>> }}
>>
>> // Face spline coupling
>>
>> {
>>
>> translate([0, 0, -3])
>>
>> facespline();
>>
>> translate([0, 0, 3])
>>
>> rotate([0, 180, 360/2/n])
>>
>> facespline();
>>
>> }
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> OpenSCAD mailing list
>> To unsubscribe send an email to discuss-leave@lists.openscad.org <mailto:discuss-leave@lists.openscad.org>
>
> --
> Cheers, Ken
> bats059@gmail.com <mailto:bats059@gmail.com>
> https://vk7krj.com <https://vk7krj.com/>
> https://vk7krj.com/running.html
> ----------------------------------------
> A baby can be defined as an ego with a noise at one end and a smell at the other.
> Your job as parents is to teach them to control all three.
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M

mikeonenine@web.de

Sat, Sep 21, 2024 1:48 AM

Bob Carlson

Fri, Sep 20, 2024 12:38 PM

That worked for me too. It’s funny I had to make one of these for a project. My electric golf cart (carries my clubs, not me), has an accessories connector with one of these. Below is the part I made. It’s about 30 mm across. I had to count the blades by hand and measure everything to get it since I had no idea what kind of spline this was. I can’t post the code since I use my own library and BOSL2, but the way I constructed it was to create 1 “fanBlade” and then repeat it 60 times around a circle. Each fanBlade was made by positioning a thin inner shape and a thin out shape, then hull’ing. I’ll be taking a closer look at the posted code to compare the two methods.

￼

On Sep 19, 2024, at 23:21, Michael Marx (spintel) via Discuss discuss@lists.openscad.org wrote:

I think you guys not seeing it may have Lazy Union enable.

Linear extrude works well too. The peaks and valleys can be rounded, which doesn’t seem to be possible with polyhedrons. The flat side isn’t, and needs to be filled in with a cone to make it flat.

> Bob Carlson
>
> Fri, Sep 20, 2024 12:38 PM
>
> That worked for me too. It’s funny I had to make one of these for a project. My electric golf cart (carries my clubs, not me), has an accessories connector with one of these. Below is the part I made. It’s about 30 mm across. I had to count the blades by hand and measure everything to get it since I had no idea what kind of spline this was. I can’t post the code since I use my own library and BOSL2, but the way I constructed it was to create 1 “fanBlade” and then repeat it 60 times around a circle. Each fanBlade was made by positioning a thin inner shape and a thin out shape, then hull’ing. I’ll be taking a closer look at the posted code to compare the two methods.
>
> ￼
>
> On Sep 19, 2024, at 23:21, Michael Marx (spintel) via Discuss [discuss@lists.openscad.org](mailto:discuss@lists.openscad.org) wrote:
>
> > I think you guys not seeing it may have Lazy Union enable.
Linear extrude works well too. The peaks and valleys can be rounded, which doesn’t seem to be possible with polyhedrons. The flat side isn’t, and needs to be filled in with a cone to make it flat.

BC

Bob Carlson

Wed, Sep 25, 2024 1:08 AM

I got interested in the Hirth joint problem since I now know the name and understand what’s going on. Also, the part I needed to make had a conical Hirth joint. I was curious how that could be parameterized. It turned out to be fairly simple. Here is the current state of my test program. It uses BOSL2, but not my own library. It’s set up with the customizer so it’s easy to play around with. I’m running it on OpenSCAD.24.09.20 and BOSL2 from maybe a couple of months ago. It’s not entirely debugged, but works. Using hull and cheating a little, the math is minimal. It’s all in calculating toothBaseWidth and toothHeight. The “cheat” is that I hull the tooth profile with a tiny cube at the origin. For a conical joint, the origin just moves up. Most of the code is actually there to provide the base above or below the teeth. That’s where I think bugs still lurk.

include <BOSL2/std.scad>

showTooth = false;

showLower = false;

showUpper = false;

showFit = false;

showProfile = false;

// Number of Teeth

N = 36; // Number Of Teeth

// Inner Radius

innerR = 30;

// Outer Radius

outerR = 50;

// Is the coupling conical?

conical = 10;

// Tooth Profile Angle

profileAngle = 60; // [60, 90]

// Must be >= 0, Default used when left at 0

chamfer = 0; // .1

// Explosion distance in mm

ex = 0;

module **Customizer_Limit** () {} // This actually works

$fn = 180;

tiny = 1 / 1024;

assembly();

module assembly() {

if (showTooth) {

tooth(conical);

}

if (showLower) {

teeth();

}

if (showUpper) {

up(ex == 0 ? .1 : ex)

upperTeeth();

}

if (showFit) {

teeth();

```
up(ex == 0 ? .1 : ex)
upperTeeth();
}
if (showProfile) {
toothProfile();
}
```

}

a0 = assert(conical >= 0, "Conical must be >= 0");

outerR0 = outerR + 0;

rotationAngle = 360/N;

toothBaseWidth = 2 * (sin(rotationAngle/2) * outerR0);

toothHeight = (toothBaseWidth/2) / tan(profileAngle/2) ;

toothChamfer = chamfer == 0.0 ? min(3, toothHeight * .1) : chamfer;

e0 = echo(str("Tooth Width ", toothBaseWidth));

e1 = echo(str("Tooth Height ", toothHeight));

e2 = echo(str("Tooth Chamfer ", toothChamfer));

e3 = echo(str("Tooth Profile ", profileAngle));

module upperTeeth() {

zrot(rotationAngle/2)

xrot(180)

intersection() {

difference() {

union() {

teeth0(-conical);

```
down(toothHeight/2 - toothChamfer/2) {
if (conical > 0) {
difference() {
zcyl(l = conical - toothHeight/2, r = outerR, anchor = TOP);
zcyl(l = conical - toothHeight/2, r2 = outerR, r1 = 0, anchor = TOP);
}
} else {
zcyl(l = toothHeight/2 + conical, r1 = outerR, r2 = 0, anchor = BOTTOM)
attach(BOTTOM, TOP)
zcyl(l = 1, r = outerR);
}
//attach(BOTTOM, TOP)
//zcyl(l = 1, r = outerR);
}
}
zcyl(h = 20, r = innerR, anchor = CENTER);
}
zcyl(h = 20, r = outerR, anchor = CENTER, $fn = 180);
}
```

}

module teeth() {

intersection() {

difference() {

union() {

teeth0(conical);

```
down(toothHeight/2 - toothChamfer/2) {
zcyl(l = toothHeight/2 + conical, r1 = outerR, r2 = 0, anchor = BOTTOM)
attach(BOTTOM, TOP)
zcyl(l = 1, r = outerR);
}
}
zcyl(h = 20, r = innerR, anchor = CENTER);
}
zcyl(h = 20, r = outerR, anchor = CENTER, $fn = 180);
}
```

}

module teeth0(h) {

for (i = [0 : 360/N : 359]) {

zrot(i)

tooth(h);

}

}

module tooth(h) {

hull() {

up(h)

cube(tiny, anchor = CENTER);

right(outerR0)

toothProfile();

}

}

module toothProfile() {

path = [[0, 0],

[0, toothBaseWidth],

[toothHeight, toothBaseWidth/2]];

//e0 = echo(path);

```
difference() {
yrot(-90)
left(toothHeight/2)
fwd(toothBaseWidth/2)
linear_extrude(tiny)
polygon(path);
up(toothHeight/2 - toothChamfer)
cube(toothChamfer*2, anchor = BOTTOM);
}
```

}

I got interested in the Hirth joint problem since I now know the name and understand what’s going on. Also, the part I needed to make had a conical Hirth joint. I was curious how that could be parameterized. It turned out to be fairly simple. Here is the current state of my test program. It uses BOSL2, but not my own library. It’s set up with the customizer so it’s easy to play around with. I’m running it on OpenSCAD.24.09.20 and BOSL2 from maybe a couple of months ago. It’s not entirely debugged, but works. Using hull and cheating a little, the math is minimal. It’s all in calculating toothBaseWidth and toothHeight. The “cheat” is that I hull the tooth profile with a tiny cube at the origin. For a conical joint, the origin just moves up. Most of the code is actually there to provide the base above or below the teeth. That’s where I think bugs still lurk.
include <BOSL2/std.scad>
showTooth = false;
showLower = false;
showUpper = false;
showFit = false;
showProfile = false;
// Number of Teeth
N = 36; // Number Of Teeth
// Inner Radius
innerR = 30;
// Outer Radius
outerR = 50;
// Is the coupling conical?
conical = 10;
// Tooth Profile Angle
profileAngle = 60; // [60, 90]
// Must be >= 0, Default used when left at 0
chamfer = 0; // .1
// Explosion distance in mm
ex = 0;
module __Customizer_Limit__ () {} // This actually works
$fn = 180;
tiny = 1 / 1024;
assembly();
module assembly() {
if (showTooth) {
tooth(conical);
}
if (showLower) {
teeth();
}
if (showUpper) {
up(ex == 0 ? .1 : ex)
upperTeeth();
}
if (showFit) {
teeth();
up(ex == 0 ? .1 : ex)
upperTeeth();
}
if (showProfile) {
toothProfile();
}
}
a0 = assert(conical >= 0, "Conical must be >= 0");
outerR0 = outerR + 0;
rotationAngle = 360/N;
toothBaseWidth = 2 * (sin(rotationAngle/2) * outerR0);
toothHeight = (toothBaseWidth/2) / tan(profileAngle/2) ;
toothChamfer = chamfer == 0.0 ? min(3, toothHeight * .1) : chamfer;
e0 = echo(str("Tooth Width ", toothBaseWidth));
e1 = echo(str("Tooth Height ", toothHeight));
e2 = echo(str("Tooth Chamfer ", toothChamfer));
e3 = echo(str("Tooth Profile ", profileAngle));
module upperTeeth() {
zrot(rotationAngle/2)
xrot(180)
intersection() {
difference() {
union() {
teeth0(-conical);
down(toothHeight/2 - toothChamfer/2) {
if (conical > 0) {
difference() {
zcyl(l = conical - toothHeight/2, r = outerR, anchor = TOP);
zcyl(l = conical - toothHeight/2, r2 = outerR, r1 = 0, anchor = TOP);
}
} else {
zcyl(l = toothHeight/2 + conical, r1 = outerR, r2 = 0, anchor = BOTTOM)
attach(BOTTOM, TOP)
zcyl(l = 1, r = outerR);
}
//attach(BOTTOM, TOP)
//zcyl(l = 1, r = outerR);
}
}
zcyl(h = 20, r = innerR, anchor = CENTER);
}
zcyl(h = 20, r = outerR, anchor = CENTER, $fn = 180);
}
}
module teeth() {
intersection() {
difference() {
union() {
teeth0(conical);
down(toothHeight/2 - toothChamfer/2) {
zcyl(l = toothHeight/2 + conical, r1 = outerR, r2 = 0, anchor = BOTTOM)
attach(BOTTOM, TOP)
zcyl(l = 1, r = outerR);
}
}
zcyl(h = 20, r = innerR, anchor = CENTER);
}
zcyl(h = 20, r = outerR, anchor = CENTER, $fn = 180);
}
}
module teeth0(h) {
for (i = [0 : 360/N : 359]) {
zrot(i)
tooth(h);
}
}
module tooth(h) {
hull() {
up(h)
cube(tiny, anchor = CENTER);
right(outerR0)
toothProfile();
}
}
module toothProfile() {
path = [[0, 0],
[0, toothBaseWidth],
[toothHeight, toothBaseWidth/2]];
//e0 = echo(path);
difference() {
yrot(-90)
left(toothHeight/2)
fwd(toothBaseWidth/2)
linear_extrude(tiny)
polygon(path);
up(toothHeight/2 - toothChamfer)
cube(toothChamfer*2, anchor = BOTTOM);
}
}

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