Ellipse curve

Troubleshooting General Help
1

Hallo



I want to move a object (satelite) in a ellipse around another object (earth), I tried it this way



               Vector3f[] modelSatelitePoints = new Vector3f[]{
                new Vector3f(300, 50, 350),
                new Vector3f(950, 0, 0),
                new Vector3f(300, -50, -750),
                new Vector3f(-350, 0, 0),
                new Vector3f(300, 50, 350)
           };

           BezierCurve curveSatelite = new BezierCurve("modelSatelite path", modelSatelitePoints);
     
           CurveController ccSatelite = new CurveController(curveSatelite, modelSatelite);
          
           ccSatelite.setRepeatType(Controller.RT_WRAP);
           ccSatelite.setSpeed(.04f);
           ccSatelite.setAutoRotation(false);
           modelSatelite.addController(ccSatelite);
         
           rootNode.attachChild(modelSatelite);
           rootNode.updateRenderState();   



it works nearly fine, but the problem is it no closed cicle/ellipse, so when the satelite reaches the endpoint its turning looks strange.

One posibility would be to rotate the satelite around the earth, that way i would get a closed circle, but is there a way i could get it move on a ellipse?

mfg
Drake
2

You could use a setup like this:



      ©----s



Where © is a Node located at the center of your planet, and s is the satellite which is a child of ©.

that way, you can use two SpatialTransformer Controllers, one rotating ©, and one moving s forth and back along one axis - this should give you a rather elliptic ecliptic :wink: !

3

i'm going to try it out. Sounds good.

4

Try the CatmullRomCurve class, it's designed so that the object will pass through all control points. You can find it somewhere on "User Code" forum.

5

today i have some kind of brainlag



i got the rotation of s around c


Node nodeModelSatelite = new Node("nodeModelSatelite");
         nodeModelSatelite.setLocalTranslation(modelEarth.getLocalTranslation());
         nodeModelSatelite.attachChild(modelSatelite);
         
         SpatialTransformer stSatelite = new SpatialTransformer(1);
         stSatelite.setObject(nodeModelSatelite, 0, -1);

           // Assign a rotation for object 0 at time 0 to rotate 0 degrees around
           Quaternion stSateliteX0 = new Quaternion();
           stSateliteX0.fromAngleAxis(0, new Vector3f(0, 1.0f, 0.4f));
           stSatelite.setRotation(0, 0, stSateliteX0);
          
           // Assign a rotation for object 0 at time 2 to rotate 180 degrees
           Quaternion stSateliteX180 = new Quaternion();
           stSateliteX180.fromAngleAxis(FastMath.DEG_TO_RAD * 180, new Vector3f(0, 1.0f, 0.4f));
           stSatelite.setRotation(0, 2, stSateliteX180);

           // Assign a rotation for object 0 at time 4 to rotate 360 degrees
           Quaternion stSateliteX360 = new Quaternion();
           stSateliteX360.fromAngleAxis(FastMath.DEG_TO_RAD * 360, new Vector3f(0, 1.0f, 0.4f));
           stSatelite.setRotation(0, 4, stSateliteX360);

           stSatelite.interpolateMissing();
           stSatelite.setRepeatType(Controller.RT_WRAP);
           stSatelite.setSpeed(.1f);
          
           nodeModelSatelite.addController(stSatelite);
         
         rootNode.attachChild(nodeModelSatelite);
         rootNode.updateRenderState();



but i don't get the second SpatialTransformer  for it.
6

as momoko said. use the CatmullRomCurve in combination with a CurveController