Corresponding js file

src/Cameras/babylon.freeCamera.js

@@ -175,11 +175,14 @@ var BABYLON;
             }
             globalPosition.subtractFromFloatsToRef(0, this.ellipsoid.y, 0, this._oldPosition);
             this._collider.radius = this.ellipsoid;
+            //no need for clone, as long as gravity is not on.
+            var actualVelocity = velocity;
             //add gravity to the velocity to prevent the dual-collision checking
             if (this.applyGravity) {
-                velocity.addInPlace(this.getScene().gravity);
+                //this prevents mending with cameraDirection, a global variable of the free camera class.
+                actualVelocity = velocity.add(this.getScene().gravity);
             }
-            this.getScene().collisionCoordinator.getNewPosition(this._oldPosition, velocity, this._collider, 3, null, this._onCollisionPositionChange, this.uniqueId);
+            this.getScene().collisionCoordinator.getNewPosition(this._oldPosition, actualVelocity, this._collider, 3, null, this._onCollisionPositionChange, this.uniqueId);
         };
         FreeCamera.prototype._checkInputs = function () {
             if (!this._localDirection) {