Glenn

Must remember to use that, which I probably tripped over in the past
but forgot all about it.

I have matched a curve using graph paper and map out the coordinates
into a list, example 5 in the attached is a demonstration of various
shapes generated by point arrays

HTH,

Roger.

Recently though, I've been coding more polygons with variables and
expressions in the tuples, can't posit a pretty tool for that...

On 7/28/2025 7:51 AM, Jon Bondy wrote:

Excellent!  I did something similar, but not as elegant!

On 7/28/2025 9:44 AM, Glenn Butcher via Discuss wrote:

I got to using profile polygons so much I ended up writing a 'polygon
sketcher' program:

Just click in the window and it adds  points to the list.  It's
OpenSCAD-centric, copy-to-clipboard is formatted as an OpenSCAD list,
so I can paste it directly into code:

It's available here:

https://github.com/butcherg/wxpolygon

On 7/28/2025 2:46 AM, Roger Whiteley via Discuss wrote: Glenn

Must remember to use that, which I probably tripped over in the past
but forgot all about it.

I have matched a curve using graph paper and map out the coordinates
into a list, example 5 in the attached is a demonstration of various
shapes generated by point arrays

HTH,

Roger.

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

If you want bezier curves added you can use my interactive tool :
https://digirent.nl/bezier.html  to create the segments.

It's partially in dutch but not very difficult. ("Gebruik dit punt"  means
: use this point.)
// example of created segments

segments = [
[[205, 0],    [100,0],  [0, 0]],          // 0 eerste rechte lijn
met de klok mee
[[0, 0],    [0,17.5],  [0, 32]],          // 1 rechte lijn omhoog op
de 0 as
[[0, 32],    [0,41.5],  [8, 42]],        // 2 eerste curve naar
rechts omhoog bollend
[[8, 42],    [100,6],  [170,80]],          // 3 lange curve bolling
naar benedentweede curve
[[170, 80],  [185, 95],  [151, 120]],      // 4 korte curve
[[151,120],  [145, 125],  [160, 151]],    // 5
[[160,151],  [165, 160],  [168, 151]],    // 6
[[168,151],  [165, 130],  [183, 128]],    // 7
[[183,128],  [200, 130],  [197, 151]],    // 8
[[197,151],  [200, 160],  [205, 151]],    // 9
[[205,151],  [232, 120],  [185, 65]],      // 10
[[185,65],  [170, 45],  [201, 22]],        // 11
[[201,22],  [210, 15],  [205, 0]],        // 12
];

curve_points = createBezier(segments, 30);  // cretae all the points for
the desired curve
polygon(points = curve_points);

// library functions to create bezier curves
function createBezier(segments, steps_per_segment=20) =
let(
// Bereken alle punten per segment
segment_points = [
for(segment_idx = [0:len(segments)-1])
let(
segment = segments[segment_idx],
segment_result = bezier2(segment, steps_per_segment)
)
// Skip het laatste punt van elk segment behalve het
laatste (om duplicaten te vermijden)
segment_idx < len(segments) - 1
? [for(i = [0:len(segment_result)-2])
segment_result[i]]
: segment_result
]
)
// Flatten de array van arrays
[for(segment = segment_points, point = segment) point];

// Basis Bezier-functie voor 2D
function bezier2(points, steps) =
let(n = len(points) - 1)
[for(t = [0 : 1/steps : 1])
bezier_point(points, n, t)];

// Functie om een punt op de Bezier-curve te berekenen
function bezier_point(points, n, t) = n == 0 ?  points[0] : (1 - t) *
bezier_point(points, n - 1, t) + t * bezier_point([for(i = [1:n])
points[i]], n - 1, t);
module show_bezier_points(segments) {
for(segment = segments) {
for(p = segment) {
translate(p) color("red") circle(2);
}
// Teken controlelijnen
color("gray", 0.5)
for(i = [0:len(segment)-2]) {
hull() {
translate(segment[i]) circle(0.5);
translate(segment[i+1]) circle(0.5);
}
}
}

}
module polyline(points, radius = 0.5) {
for (i = [0 : len(points) - 2]) {
hull() {
translate(points[i]) circle(r = radius, $fn=20);
translate(points[i + 1]) circle(r = radius, $fn=20);
}
}
}

Met vriendelijke groet,

Matthieu Hendriks

email: mhendriks@digirent.nl

Glenn Butcher via Discuss schreef op 2025-07-28 15:54:

Recently though, I've been coding more polygons with variables and
expressions in the tuples, can't posit a pretty tool for that...
On 7/28/2025 7:51 AM, Jon Bondy wrote:

Excellent!  I did something similar, but not as elegant!

On 7/28/2025 9:44 AM, Glenn Butcher via Discuss wrote:

I got to using profile polygons so much I ended up writing a 'polygon
sketcher' program:

Just click in the window and it adds  points to the list.  It's
OpenSCAD-centric, copy-to-clipboard is formatted as an OpenSCAD list, so I
can paste it directly into code:

It's available here:

https://github.com/butcherg/wxpolygon

On 7/28/2025 2:46 AM, Roger Whiteley via Discuss wrote:

Glenn

Must remember to use that, which I probably tripped over in the past but
forgot all about it.

I have matched a curve using graph paper and map out the coordinates into
a list, example 5 in the attached is a demonstration of various shapes
generated by point arrays

HTH,

Roger.

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

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Hey, this is a great  tool!

I am just wondering how to add /remove points from within  one bezier
curve ...

On Mon, Jul 28, 2025 at 4:14 PM Matthieu Hendriks via Discuss
discuss@lists.openscad.org wrote:

If you want bezier curves added you can use my interactive tool :
https://digirent.nl/bezier.html  to create the segments.

It's partially in dutch but not very difficult. ("Gebruik dit punt"
means : use this point.)

// example of created segments

segments = [
[[205, 0],    [100,0],  [0, 0]],          // 0 eerste rechte lijn met
de klok mee
[[0, 0],    [0,17.5],  [0, 32]],          // 1 rechte lijn omhoog op
de 0 as
[[0, 32],    [0,41.5],  [8, 42]],        // 2 eerste curve naar
rechts omhoog bollend
[[8, 42],    [100,6],  [170,80]],          // 3 lange curve bolling
naar benedentweede curve
[[170, 80],  [185, 95],  [151, 120]],      // 4 korte curve
[[151,120],  [145, 125],  [160, 151]],    // 5
[[160,151],  [165, 160],  [168, 151]],    // 6
[[168,151],  [165, 130],  [183, 128]],    // 7
[[183,128],  [200, 130],  [197, 151]],    // 8
[[197,151],  [200, 160],  [205, 151]],    // 9
[[205,151],  [232, 120],  [185, 65]],      // 10
[[185,65],  [170, 45],  [201, 22]],        // 11
[[201,22],  [210, 15],  [205, 0]],        // 12
];

curve_points = createBezier(segments, 30);  // cretae all the points
for the desired curve
polygon(points = curve_points);

// library functions to create bezier curves

function createBezier(segments, steps_per_segment=20) =
let(
// Bereken alle punten per segment
segment_points = [
for(segment_idx = [0:len(segments)-1])
let(
segment = segments[segment_idx],
segment_result = bezier2(segment, steps_per_segment)
)
// Skip het laatste punt van elk segment behalve het laatste (om
duplicaten te vermijden)
segment_idx < len(segments) - 1
? [for(i = [0:len(segment_result)-2]) segment_result[i]]
: segment_result
]
)
// Flatten de array van arrays
[for(segment = segment_points, point = segment) point];

// Basis Bezier-functie voor 2D
function bezier2(points, steps) =
let(n = len(points) - 1)
[for(t = [0 : 1/steps : 1])
bezier_point(points, n, t)];

// Functie om een punt op de Bezier-curve te berekenen
function bezier_point(points, n, t) = n == 0 ?  points[0] : (1 - t) *
bezier_point(points, n - 1, t) + t * bezier_point([for(i = [1:n])
points[i]], n - 1, t);
module show_bezier_points(segments) {
for(segment = segments) {
for(p = segment) {
translate(p) color("red") circle(2);
}
// Teken controlelijnen
color("gray", 0.5)
for(i = [0:len(segment)-2]) {
hull() {
translate(segment[i]) circle(0.5);
translate(segment[i+1]) circle(0.5);
}
}
}

}
module polyline(points, radius = 0.5) {
for (i = [0 : len(points) - 2]) {
hull() {
translate(points[i]) circle(r = radius, $fn=20);
translate(points[i + 1]) circle(r = radius, $fn=20);
}
}
}

Met vriendelijke groet,

Matthieu Hendriks

email: mhendriks@digirent.nl

Glenn Butcher via Discuss schreef op 2025-07-28 15:54:

Recently though, I've been coding more polygons with variables and
expressions in the tuples, can't posit a pretty tool for that...

On 7/28/2025 7:51 AM, Jon Bondy wrote:

Excellent!  I did something similar, but not as elegant!

On 7/28/2025 9:44 AM, Glenn Butcher via Discuss wrote:

I got to using profile polygons so much I ended up writing a 'polygon
sketcher' program:

Just click in the window and it adds  points to the list.  It's
OpenSCAD-centric, copy-to-clipboard is formatted as an OpenSCAD list,
so I can paste it directly into code:

It's available here:

https://github.com/butcherg/wxpolygon

On 7/28/2025 2:46 AM, Roger Whiteley via Discuss wrote: Glenn

Must remember to use that, which I probably tripped over in the past
but forgot all about it.

I have matched a curve using graph paper and map out the coordinates
into a list, example 5 in the attached is a demonstration of various
shapes generated by point arrays

HTH,

Roger.

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