How does one create their own interpolation

Question

I am currently working on a tile-based environment in which the user controls a tank. I have been attempting to use interpolators to smooth out the movement between tiles, but I have had a lot of trouble acheiving the desired effects. From what I have gathered from various posts is that the interpolator classes are only useful for repeating animations (please correct me if this statement is wrong).
My question then is:
How does one create their own or methods which simulates the interpolation behavior; I am particularly interested in the PositionInterpolator for translating the missles fired by the tank.
I attempted to do this several times, but I have failed. Here is one of my attempts:
public void fire()
     show(); //show the missle geometry
     int TRANSLATION_TIME = 1000; //blast alive for 5 seconds
     float DISTANCE = 20.0f; //missle travels a distance of 20 units
     //interpolate path
     long startTime = System.currentTimeMillis();
     long endTime = startTime +TRANSLATION_TIME;
     long interval = endTime - startTime;
     float translationPercent;
     float lastTransPercent = 0;
     float dist;
     Transform3D translate = new Transform3D();
     while(System.currentTimeMillis() < endTime && !collision)
     interval = System.currentTimeMillis() - startTime;
     translationPercent = (float)interval/TRANSLATION_TIME;
     dist = DISTANCE*(translationPercent - lastTransPercent);
     lastTransPercent = translationPercent;
     translate.setTranslation(new Vector3f(0.0f, 0.0f, -dist));
     interpolate(translate);
public void interpolate(Transform3D translate)
     Transform3D t3d = new Transform3D();
     missleTG.getTransform(t3d);
     t3d.mul(translate);
     missleTG.setTransform(t3d);     
What happens using this code is that the missle just waits at its initial location until the TRANSLATION_TIME has passed, and then jumps to the final position -- the missle does not smoothly translate to the final location. Are there any explainations out there for this behaviors.
-Thanks in advance

Answer 1

Hi,
I'm also working on a game environment where the user can move around in a spaceship and fire missiles etc...
I haven't looked much at interpolators, but I use Behaviors for everything I need to move/rotate/scale...
You can for example create your own behavior (by extending the Behavior class) and set it up to move the missile when you press a specific key, or when any other kind of event takes place...
You should check the documentation for the Behavior class.
Hope this helps...