We closed this forum 18 June 2010. It has served us well since 2005 as the ALPHA forum did before it from 2002 to 2005. New discussions are ongoing at the new URL http://forum.processing.org. You'll need to sign up and get a new user account. We're sorry about that inconvenience, but we think it's better in the long run. The content on this forum will remain online.
Index › Programming Questions & Help › Syntax Questions › A 'sphere' of 3D spheres
‹ Previous Topic | Next Topic ›
Pages: 1 2 
A 'sphere' of 3D spheres? (Read 1360 times)
Cycleswithin
A 'sphere' of 3D spheres?
Mar 4th, 2008, 12:28pm  
Hey, I'm trying to create something I have visualised in my head, but am fairly new to programming, especially with 3D work.

What i'm trying to achieve are a number of spheres positioned in a 'sphere' configuration in 3D, if you see what I mean. Imagine the nucleus of an atom, but with space between the spheres.

I can do a pseudo-2D version (although I think i'm doing it the long way), which might help to show what I'd like...

Code:
float x, y, z;
float angle;
float radius = 180.0;
float frequency = 45;

void setup() {
  size(400, 400);
  background(0);
  smooth();
  noStroke();
}

void draw() {
  background(0);
  for (int i=0; i<360; i+=45) {
    x = width/2 + cos(radians(angle))*(radius/2);
    y = height/2 + sin(radians(angle))*(radius/2);
    rectMode(CENTER);
    fill(255);
    ellipse (x, y, 10, 10);
    angle -= frequency;
  }

  for (int i=0; i<360; i+=45) {
    x = width/2 + cos(radians(angle))*(radius);
    y = height/2 + sin(radians(angle))*(radius);
    rectMode(CENTER);
    fill(255);
    ellipse (x, y, 20, 20);
    angle -= frequency;
  }
}


However, I'm not sure how to go to 3D and get the desired result - the steps needed? Obviously I need to add a Z dimension! Any ideas of what I need to do?
Back to top
 
 
JohnG
Re: A 'sphere' of 3D spheres?
Reply #1 - Mar 4th, 2008, 1:03pm  
Whilst a circle is fairly easy, it gets quite a bit more complicated on a sphere if you want an even spacing of small-spheres.
See: http://www.cgafaq.info/wiki/Evenly_distributed_points_on_sphere
or
http://www.ogre.nu/sphere.htm
for a couple of methods/discussion of the problem.
Back to top
 
 
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #2 - Mar 4th, 2008, 4:05pm  
Hey thanks for the links - interesting reading.

I don't know if you've heard of a program called Mathematica, initiated by that chap Wolfram (who wrote 'A New Kind Of Science'). Any, it has similarities to Processing, and there is an example program with something similar to what i'd like to do here: http://demonstrations.wolfram.com/ClusterOf92Spheres/

Although, this screenshot is probably more relevant: http://demonstrations.wolfram.com/ClusterOf92Spheres/HTMLImages/index.en/popup_3.gif

I've look at the source code for this, but it's in a completely different language, and anyway it just seems like it has an in-built shape ('icosahedron') which it plots the spheres on (some on faces, some on vertices) etc.
Back to top
 
 
eskimoblood
Re: A 'sphere' of 3D spheres?
Reply #3 - Mar 4th, 2008, 4:25pm  
The surfaceLib which allows you to create spheres has the methode: coords()(http://www.eskimoblood.de/surfacelib/surface_method_coords.htm) which gives you the coordinates of your sphere surface.

Code:

Sphere s =new Sphere(this, 10, 10); // gives you a sphere with 10*10 points
float [][][] corrds =s.coords(); //get the coords array
for(int i=0; i<coords.length; i++){
for(int j=0; j<coords[i].length; j++){
float[] xyz = <coords[i][j]; //an array with the x,y and z coordinate
}
}
Back to top
 
Andreas Köberle {eskimoblood}
222550793  
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #4 - Mar 7th, 2008, 8:40pm  
Thanks, that looks like it could be an answer! I'll check it out...
Back to top
 
 
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #5 - Mar 9th, 2008, 2:20pm  
I've had a play with this (great library by the way)...

Code:

import surface.calculation.*;
import surface.*;

Sphere s;

void setup(){
  size(500,300,P3D);
  
  s=new Sphere(g, 10, 10);
  float [][][] coords =s.coords(); //get the coords array
  print(coords);
  for(int i=0; i<coords.length; i++){
	  for(int j=0; j<coords[i].length; j++){
	    float[] xyz = coords[i][j]; //an array with the x,y and z coordinate
	    //print(xyz);
	    print(coords[i][j]);
    }
  }
}

void draw(){
  background(#FAFAFA);
  lights();
  
  translate(width/2,height/2);
  rotateX(radians(frameCount/PI));
  rotateY(radians(frameCount/PI));
  rotateZ(radians(frameCount/PI));
  s.setScale(150);
  
  noStroke();
  fill(#FF6724);
  
  s.draw();
}


And the array only seems to spit out (i'm printing it):
Code:
[F@193a66f
[F@93d6bc
[F@be0e27...
...etc.


Although it is 100 (as you would expect as the sphere is 10*10)?
Back to top
 
 
eskimoblood
Re: A 'sphere' of 3D spheres?
Reply #6 - Mar 9th, 2008, 7:23pm  
Every array holds the coordinates for the 3d point, so you need to translate with this point and draw your sphere:

Code:

void draw(){
float [][][] coords =s.coords(); //get the coords array
  for(int i=0; i<coords.length; i++){
   for(int j=0; j<coords[i].length; j++){
     float[] xyz = coords[i][j]; //an array with the x,y and 
	 pushMatrix();
	 translate(xyz[0], xyz[1], xyz[2]);
	 drawYourSpheresHere
	 popMatrix();
    }
  } 
}
Back to top
 
Andreas Köberle {eskimoblood}
222550793  
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #7 - Mar 9th, 2008, 7:41pm  
Oh I see, thanks...! So it's like a hierachy of arrays?

Arrays and texturing 3D surfaces are definately my weaknesses in Processing at the moment.
Back to top
 
 
eskimoblood
Re: A 'sphere' of 3D spheres?
Reply #8 - Mar 9th, 2008, 9:31pm  
Yes, the coordinates are stored in a three dimensional array.
Back to top
 
Andreas Köberle {eskimoblood}
222550793  
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #9 - Mar 17th, 2008, 5:33pm  
Hey, still having problems with this.

Drawing a sphere results in it being displayed in the centre.

Using the following...
Code:

println("X equals " + xyz[0]);
println("Y equals " + xyz[1]);
println("Z equals " + xyz[2]);


Shows that it's spitting out really odd values...
Code:

X equals 0.0
Y equals -0.0
Z equals 1.0
X equals 0.05939133
Y equals -0.33682406
Z equals 0.9396926
X equals 0.11161919
Y equals -0.6330222
Z equals 0.76604444
X equals 0.15038413
Y equals -0.8528685
Z equals 0.49999997
X equals 0.17101052
Y equals -0.96984625
Z equals 0.1736481
X equals 0.17101051
Y equals -0.9698462
Z equals -0.1736483
X equals 0.15038411
Y equals -0.85286844
Z equals -0.50000006
X equals 0.11161916
Y equals -0.633022
Z equals -0.7660446
X equals 0.059391305
Y equals -0.3368239
Z equals -0.9396927
X equals -1.5180845E-8
Y equals 8.609462E-8
Z equals -1.0
etc.....


If they were between 1.0 and -1.0 I could probably see why, but odd values like 8.609462E-8 and -1.5180845E-8 get thrown up (that even include letters). Any clues?
Back to top
 
 
JohnG
Re: A 'sphere' of 3D spheres?
Reply #10 - Mar 17th, 2008, 5:40pm  
8.609462E-8 means 0.00000008609462
"E-8" is notation for "times ten to the power -8" and it just shorthand for expressing really small (or big) numbers without having lots of zeros flying around.
Back to top
 
 
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #11 - Mar 17th, 2008, 8:00pm  
Ah right I see...

Isn't it odd though that they are really small numbers?
Back to top
 
 
eskimoblood
Re: A 'sphere' of 3D spheres?
Reply #12 - Mar 17th, 2008, 8:59pm  
No it isn't, cause these are values for an sphere with a radius of 1. So all you have to do is to multiply this values with the radius of your choice.
Back to top
 
Andreas Köberle {eskimoblood}
222550793  
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #13 - Mar 18th, 2008, 2:29pm  
Ah OK - I used s.setScale(150); before that part so I assumed it would change the values also.
Back to top
 
 
Cycleswithin
Re: A 'sphere' of 3D spheres?
Reply #14 - Mar 20th, 2008, 8:59pm  
I've got this working, and it looks quite cool - lots of potential here methinks...

...

However it does run quite slow - but this is understandable because it is calculating the coordinates and then creating an array with all those values every time around the draw() loop!
Back to top
 
 
Pages: 1 2 
‹ Previous Topic | Next Topic ›