How to - '2d fluid sim' ?

beginners
#1

Hi,

I’m looking for any advices that could help me to reproduction this with OF - http://www.smallfly.com/of/test-2.mov - it’s almost 2d fluid sim.

I tried using box2d but I don’t get something as reactive as what the video shows, and I don’t think I will.

The idea is to have the same motion/reaction and to be able to move any of the ‘nodes’, not just one extremity as is the video.

Thanks,

-h

#2

Well…correction. I’m maybe getting somewhere using box2d.

-h

#3

Box2D is probably massive overkill, but I wouldn’t be surprised if you needed something special for solving spring networks.

(If I understand it correctly, it’s just a network of n-1 springs attaching n objects?)

#4

Yes this just a chain of n-1 springs attaching n objects. Any of the objects can be a ‘handle’.
Using box2d give me the opportunity to have access to other physics properties if I need (i.e. gravity), but I 'm still interested to approach this in a different way.

One thing I want to achieve, is to have several of those chains and to detect the ‘collisions’ and overlap between them. This in order to detect/define the shapes created by the overlap of 2 chains.

#5

Ok, nice… if you need any more physics besides the spring (e.g., gravity) then Box2D is probably perfect.

Looking forward to seeing what you make… :slight_smile:

#6

Hi,

If you wanted to roll your own springs, here is some example code, assuming it is part of a particle class:

  
  
void Particle::spring(Particle * p, float const k, float const springDist, float const drag) {  
	float dis = pos.distance(p->pos); //distance between two particles  
	dis = springDist-dis; //distance from resting position of spring  
  
	// find the direction to the other particle  
	ofxVec3f dir = ((ofxVec3f)(p->pos - pos)).normalized();   
  
	float force = (-k/(mass*p->mass))*(dis/drag); //spring force equation  
  
	//add velocity to both particles  
	vel += dir*(force/mass);  
	p->vel += dir*(-force/p->mass);  
}

Have fun,
Sounds like a cool project!