diff --git a/core/src/sagittarius/SagittariusGame.java b/core/src/sagittarius/SagittariusGame.java
index 5e417c1..f07989a 100644
--- a/core/src/sagittarius/SagittariusGame.java
+++ b/core/src/sagittarius/SagittariusGame.java
@@ -9,7 +9,7 @@ public class SagittariusGame extends Game {
 
     // Constants
     public static float G = 100;
-    public static boolean debugMode = false;
+    public static boolean debugMode = true;
 
     private static Game game;
 
diff --git a/core/src/sagittarius/model/Arrow.java b/core/src/sagittarius/model/Arrow.java
index 4cfce7c..73938ce 100644
--- a/core/src/sagittarius/model/Arrow.java
+++ b/core/src/sagittarius/model/Arrow.java
@@ -1,5 +1,6 @@
 package sagittarius.model;
 
+import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
 import java.util.Random;
 
@@ -215,26 +216,16 @@ public class Arrow extends EntityQuad {
      * @param timeStep time period used for the integration.
      * @return an array of vertices describing the trajectory of the Arrow.
      */
-    static float[] traj(float angle, float power, Player shooter, int iterations, float timeStep) {
-        ArrayList<Float> path = new ArrayList<Float>();
+    static Trajectory computeTrajectory(float angle, float power, Player shooter, int iterations, float timeStep) {
+        Trajectory traj = new Trajectory(iterations);
         Arrow dummyArrow = new Arrow(angle, power, shooter, true);
         for (int i = 0; i < iterations; i++) {
             dummyArrow.integrationVerlet(timeStep);
-            path.add(dummyArrow.getX());
-            path.add(dummyArrow.getY());
+            traj.add(dummyArrow.getPosition());
             if ( dummyArrow.hasLanded() || dummyArrow.hasHit() ) { break; }
         }
 
-        // TODO : optimize, lots of useless stuff + change name
-        // or ignore and use adapters
-
-        final float[] arr = new float[path.size()]; // utiliser le count de la fonction, faire tab size iteration*2, et draw avec count
-        int index = 0;                              // TODO: créer objet Trajectory, avec un float[iteration*2] et un actualSize;
-        for (final Float value: path) {
-           arr[index++] = value;
-        }
-
-        return arr;
+        return traj;
     }
 
     @Override
diff --git a/core/src/sagittarius/model/Bow.java b/core/src/sagittarius/model/Bow.java
index 79fb42d..61cda43 100644
--- a/core/src/sagittarius/model/Bow.java
+++ b/core/src/sagittarius/model/Bow.java
@@ -60,10 +60,8 @@ public class Bow extends Actor {
             if (power > 50) shapes.setColor(Color.RED);
             shapes.line(this.anchor, GameScreen.worldCursor);
             if (aimAssist) {
-                float[] traj = Arrow.traj(angle, power, GameScreen.playerCurrent, 500, 0.03f);
-                if (traj.length > 2) {
-                    shapes.polyline(traj);
-                }
+                Trajectory traj = Arrow.computeTrajectory(angle, power, GameScreen.playerCurrent, 500, 0.03f);
+                shapes.polyline(traj.path, 0, traj.actualSize);
             }
         }
     }
diff --git a/core/src/sagittarius/model/Trajectory.java b/core/src/sagittarius/model/Trajectory.java
new file mode 100644
index 0000000..8491db0
--- /dev/null
+++ b/core/src/sagittarius/model/Trajectory.java
@@ -0,0 +1,24 @@
+package sagittarius.model;
+
+import com.badlogic.gdx.math.Vector2;
+
+public class Trajectory {
+
+    float[] path;
+    int actualSize;
+
+    public Trajectory(int iterations) {
+        path = new float[2*iterations];
+    }
+
+    public void add(float x, float y) {
+        path[actualSize++] = x;
+        path[actualSize++] = y;
+    }
+
+    public void add(Vector2 vec) {
+        path[actualSize++] = vec.x;
+        path[actualSize++] = vec.y;
+    }
+
+}