code: public static Xml exports(Force force)
      {
          Check.notNull(force);
  
          final Xml node = new Xml(NODE_FORCE);
          node.writeDouble(ATT_VX, force.getDirectionHorizontal());
          node.writeDouble(ATT_VY, force.getDirectionVertical());
          node.writeDouble(ATT_VELOCITY, force.getVelocity());
          node.writeDouble(ATT_SENSIBILITY, force.getSensibility());
  
          return node;
      }
docs: Export the force node from data.
  
  @param force The force reference (must not be <code>null</code>).
  @return The force data.
  @throws LionEngineException If unable to read node.