steering behaviours

Ok so I'm going nuts over this, The source I'm reading from is here:

http://www.red3d.com/cwr/steer/gdc99/

If you can be bothered reading that, the main concern is with the arrival behaviour. I have setup my object exactly the same as the page says

Simple Vehicle Model:
mass scalar
position vector
velocity vector
max_force scalar
max_speed scalar
orientation N basis vectors

Code:

---

private var p:Vector; //position
private var v:Vector; //velocity
private var f:Vector; //force
               
private var mass:Number;
private var maxForce:Number;
private var maxSpeed:Number;

---

*I have left out orientation and added in force which is used as steering

now when converting this arrival code into flash:

target_offset = target - position
distance = length (target_offset)
ramped_speed = max_speed * (distance / slowing_distance)
clipped_speed = minimum (ramped_speed, max_speed)
desired_velocity = (clipped_speed / distance) * target_offset
steering = desired_velocity - velocity

Code:

---

var d:Vector = target.subNew(p); //target offset
                       
var dist:Number = d.length;
var speed:Number = maxSpeed * (dist / 100);
                       
speed = Math.min(speed, maxSpeed);
                       
var dvx = (speed / dist) * d.x;
var dvy = (speed / dist) * d.y;
                       
f.x = dvx - v.x;
f.y = dvy - v.y;

---

and then I update the object exactly like the paper describes:

steering_force = truncate (steering_direction, max_force)
acceleration = steering_force / mass
velocity = truncate (velocity + acceleration, max_speed)
position = position + velocity

Code:

---

clamp(f, maxForce);
                       
var ax = f.x / mass;
var ay = f.y / mass;
                       
v.x += ax;
v.y += ay;
                       
clamp(v, maxSpeed);

p.x += v.x;
p.y += v.y;

---

the clamp functions looks like:

Code:

---

function clamp(n, max){

var len = n.length;

if(len > max){

n.x /= len
n.y /= len

n.x *= max
n.y *= max
}
}

---

But the object continues past the target, as if it were elastic

can somebody point out what I have done wrong here, I have found several papers on this all which are exactly the same, use the same formulas, but I can't seem to re-create it in flash.

hmm, was playing around and it seems mass is the culprit for the overshooting, I guess that makes sense since the arrive function knows nothing about the mass of the object; and assumes the force given is the force applied