# How to make Gear Ratios

**URL:** <https://discourse.processing.org/t/how-to-make-gear-ratios/15221>\
**Category:** Project Guidance\
**Created:** [November 4, 2019, 4:03pm UTC](https://discourse.processing.org/t/how-to-make-gear-ratios/15221 "2019-11-04T16:03:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![locky12](https://avatars.discourse-cdn.com/v4/letter/l/ecae2f/32.png) [@locky12](https://discourse.processing.org/u/locky12)\
**Post date:** [November 4, 2019, 4:03pm UTC](https://discourse.processing.org/t/how-to-make-gear-ratios/15221/1 "2019-11-04T16:03:28Z")

</div>

I am writing a software in Java, for my Computer Science IA that shows how gear Ratios work, However the only problem with it is that I have no idea of how to draw a gear in processing, please could somebody help me out?

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<div class="post-metadata">

**Author:** ![kll](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/kll/32/964_2.png) [@kll](https://discourse.processing.org/u/kll)\
**Post date:** [November 5, 2019, 1:54am UTC](https://discourse.processing.org/t/how-to-make-gear-ratios/15221/4 "2019-11-05T01:54:22Z")

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ok, when i google it i found 2 examples, one archived at open processing and one at old forum  
working BOTH in processing 3.5.3 without problem.

so you want to learn how to make it? ( project guidance? )

-a- you have the math  
RATIO / radius / diameter / distance of the two circles / circumference /  
already in processing?

-b- need to decide about HMI /operation  
what are the parameter to change / how the user can do that.

-c- display the set and calculated values on the canvas

-d- draw the 2 circles in correct distance ( put a marker on )  
and rotate them

* * *

so without the difficult math and graphic part about the

> gear teeth profile

you already can show something

* * *

-e- the next approximation would be just to put circles on the circumference  
as symbols for the gear teeth  
to show the gear basics : even sized and spaced teeth ( not angle spaced )  
on two different diameters.  
and visualized the math / data for it too.

-f-  
well for the main fun, to draw

> **[Involute gear](https://en.wikipedia.org/wiki/Involute_gear)**
>
> The involute gear profile is the most commonly used system for gearing today, with cycloid gearing still used for some specialties such as clocks. In an involute gear, the profiles of the teeth are involutes of a circle. The involute of a circle is the spiraling curve traced by the end of an imaginary taut string unwinding itself from that stationary circle called the base circle, or (equivalently) a triangle wave projected on the circumference of a circle.
> The involute gear profile was a funda...

( for long lasting mechanic )  
you should experiment in a extra little drawing project first.  
please show us that too.

* * *

hope see some good code and show ( pictures ) here soon.

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<div class="post-metadata">

**Author:** ![GoToLoop](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/gotoloop/32/86_2.png) [@GoToLoop](https://discourse.processing.org/u/GoToLoop)\
**Post date:** [November 5, 2019, 9:57am UTC](https://discourse.processing.org/t/how-to-make-gear-ratios/15221/5 "2019-11-05T09:57:14Z")

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> [@locky12](#):
>
> … I have no idea of how to draw a gear in Processing,

[Studio.ProcessingTogether.com/sp/pad/export/ro.9WrTp2GiTlnLW](http://Studio.ProcessingTogether.com/sp/pad/export/ro.9WrTp2GiTlnLW)

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<div class="post-metadata">

**Author:** ![glv](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/glv/32/18785_2.png) [@glv](https://discourse.processing.org/u/glv)\
**Post date:** [November 5, 2019, 12:57pm UTC](https://discourse.processing.org/t/how-to-make-gear-ratios/15221/6 "2019-11-05T12:57:07Z")

</div>

There are many approaches to this.

My video will share some insight on how I built the gears:

[![](https://img.youtube.com/vi/RTZvgVu4LeU/maxresdefault.jpg "Planetary Gears") ](https://www.youtube.com/watch?v=RTZvgVu4LeU)

A visual approach (colours, lines, plots, display data, etc) helped me to develop and refine the code.

I started with a simple shape and later manipulated the vertices with a lot of math; fortunately, the math comes easily to me and I was familiar with the mechanics of gears and gear ratios.

My approach to this was a personal exercise; I enjoy coding from scratch and did not look at any other code or reference formulas. I get great satisfaction from this approach but it is not for everyone.

After all, that was said and done I created a gear class to make and move any gear.  
Planetary gears were my final challenge.  
🙂

I am sharing a snippet of my early code (its messy!) to show how I started:

```auto
PShape s; // The PShape object

float a = 15;
float d = 15;
float pitch1 = 60/2;
float gWidth = 0;
float gsa = 5;
float gsd = 1;

PVector g3, g4, g5, g6, g7, g8;

void setup()
  {
  size(300, 100, P3D);
  
  s = createShape();
  s.beginShape();

  s.fill(255, 255, 0);
  s.noStroke();

  s.vertex(-a, -0, gWidth); s.vertex(-a, -pitch1/2+gsa+gsd, gWidth); 

  s.vertex(-a, -pitch1/2+gsa+gsd); s.vertex(0, -pitch1/2 +gsd, gWidth);
  s.vertex(0, -pitch1/2+gsd); s.vertex(+d, -pitch1/2, gWidth);          

  s.vertex(d, -pitch1/2); s.vertex(+d, +pitch1/2, gWidth); 

  s.vertex(+d, pitch1/2); s.vertex(0, pitch1/2-gsd, gWidth);   
  s.vertex(0, pitch1/2 -gsd); s.vertex(-a, pitch1/2-(gsa+gsd), gWidth );

  s.vertex(-a, pitch1/2-(gsa+gsd)); s.vertex(-a, -0, gWidth);    
  s.endShape(CLOSE); 
  
  g3 = new PVector(0, 0);
  g4 = new PVector(0, 0);
  g5 = new PVector(0, 0);
  g6 = new PVector(0, 0);  
  g7 = new PVector(0, 0);
  g8 = new PVector(0, 0);   
  }
  
void draw()
  {
  background(0);

//Shape  
  shape(s, width/3, height/2);
   
//Lines   
  translate(width/2+15, height/2); 
  strokeWeight(2);
  stroke(255, 255, 0);
  
  line(-a, -0, gWidth, -a, -pitch1/2+gsa+gsd, gWidth); 

  line(-a, -pitch1/2+gsa+gsd, gWidth, 0, -pitch1/2 +gsd, gWidth);
  line(0, -pitch1/2+gsd, gWidth, +d, -pitch1/2, gWidth);          

  line(d, -pitch1/2, gWidth, +d, +pitch1/2, gWidth); 

  line(+d, pitch1/2, gWidth, 0, pitch1/2-gsd, gWidth);   
  line(0, pitch1/2 -gsd, gWidth, -a, pitch1/2-(gsa+gsd), gWidth );

  line(-a, pitch1/2-(gsa+gsd), gWidth, -a, -0, gWidth);    
    
//PVectors
  
  translate(width/4-15, 0); 
  
  float ab = 15;
  float pitch = 60/2;
  
  g3.set(ab/2, -pitch/2);
  g4.set(ab/2, pitch/2);
  
  g5.set(-ab/2, -pitch/2);
  g6.set(-ab/2, pitch/2);
  
  g7.set(-1.5*ab, -10);
  g8.set(-1.5*ab, 10);
  
  strokeWeight(2);
  beginShape(POINTS);
  vertex(g7.x, g7.y);
  vertex(g5.x, g5.y);
  vertex(g3.x, g3.y);         
  vertex(g4.x, g4.y);
  vertex(g6.x, g6.y);
  vertex(g8.x, g8.y);
  endShape();  
  }

```

After that I used a lot of math to manipulate the vertices.

My final code is much more refined than above.  
I will not be sharing my final code.

Enjoy the journey!

Lots of resources here:

> **[Welcome to Processing!](https://processing.org/)**
>
> Processing is a flexible software sketchbook and a language for learning how to code. Since 2001, Processing has promoted software literacy within the visual arts and visual literacy within technology…

🙂