Mobius Strip Animation

Simple Mobius Strip
Enjoy!

// Author:      GLV
// Date:        2019-08-08 
// Description: Simple Mobius strip
// References: 
// https://en.wikipedia.org/wiki/M%C3%B6bius_strip

PShape m1;
boolean vTog = true;
boolean tTog = true;
float thX, thY;
float u, v, x, y, z, r;
int steps;

public void settings()
  {  
  size(1280, 1024, P3D);
  }

public void setup()
  {
  ortho();
  }

public void draw()
  {
  background(0);
  lights();
  translate(width/2, height/2);
  lights();  
  thY += TAU/2000;
  rotateY(thY);
  
  thX += TAU/3000;
  rotateX(thX);  
  
  if (frameCount%100 == 0) vTog = !vTog;
  if (frameCount%200== 0) tTog = !tTog;
  
  if (vTog)
    {
    noStroke();
    fill(0, 255, 0);
    }
  else
    {
    stroke(0, 255, 0);
    noFill();
    }
    
  mobius();
  shape(m1);
  }

public void mobius()
  { 
  steps = 100;  
  r = 350;
  v = 60;  
  u = 0;
 
  m1 = createShape();
  if (tTog) 
    m1.beginShape(TRIANGLE_STRIP);
  else
    m1.beginShape(QUAD_STRIP);
    
  //integer step
  //for (int step = 0; step <= steps; step++)
  //  {
  //  u = step*(TAU/steps);  
  
  //float step
  for (float th = 0; th<=TAU+TAU/100; th+=TAU/steps)
    {
    u = th;       
    mobius2(r, -v, u);
    m1.normal(+1, 0, 0);
    //m1.fill(color(255, 255, 0));    
    m1.vertex(x, y, z);

    m1.normal(-1, 0, 0);
    //m1.fill(color(255, 0, 0));    
    mobius2(r, v, u);
    m1.vertex(x, y, z);
    }
  m1.endShape();
  }    

public void mobius2(float radius, float v, float u)
  { 
  x = (radius + v * cos(u/2)) * cos(u);
  y = (radius + v * cos(u/2)) * sin(u);
  z = v * sin(u/2);
  }


:slight_smile:

Animated GIF to follow soon…

2 Likes

Thanks for sharing. Impressive.

Question: I don’t think that’s the classical Moebius strip where you cut a ring of paper and glue it together again, rotated 180 degrees.

This one is simplified.

Am I right?

In the German Wikipedia there are two different formulas.

Chrisir

1 Like

It is a Möbius strip as defined here:

Tweaked my code and it draws this:

:slight_smile:

2 Likes

I did some further exploration of this and posted a video here:

:slight_smile:

4 Likes

Thank you for sharing this!

Very nice edgeless rainbow effect.

1 Like

Seamless Möbius strip:

// Author:      GLV
// Date:        2019-08-12 
// Description: Seamless Mobius strip
// 2 extra transparent QUAD_STRIPS added to acheive this

PShape m;
float thX, thY, thZ;
float x, y, z;
int steps;
int addStep = 2; // Change this to -1, 0, 1, 2

public void settings()
  {  
  size(1280, 1024, P3D);
  }

public void setup()
  {
  ortho();
  }

public void draw()
  {  
  background(0);
  lights();
  surface.setTitle(str(frameRate));
  
  thY += TAU/1000;
  thX += TAU/2000;
  thZ += TAU/1000; 
 
 pushMatrix();
  translate(width/2, height/2);
  rotateY(thY);
  rotateX(thX);
  rotateZ(thZ);  

  noStroke();
  mobius(100, 300, 80, 0);
  shape(m);   
 popMatrix();
  }
 
public void mobius(int steps, float r, float v, float u)
  { 
  m = createShape();
  m.beginShape(QUAD_STRIP);
  for (int step = 0; step < (steps+1) + addStep; step++) // 2 steps added for seamless mobius strip
    {
    u = step*(TAU/steps);  

    if (step > steps)
      m.fill(color(255, 128, 0, 0));   //100% transparent
    else
      m.fill(color(255, 128, 0, 255)); //100% opaque
     
    mobEq(r, -v, u);
    m.vertex(x, y, z);

    mobEq(r, v, u);
    m.vertex(x, y, z);
    }
  m.endShape();
  }

public void mobEq(float radius, float v, float u)
  { 
  x = (radius + v * cos(u/2)) * cos(u);
  y = (radius + v * cos(u/2)) * sin(u);
  z = v * sin(u/2);
  }

1 Like