def definir_escala(self, escala):
        self._escala = escala
        self.vertices = [(convertir_a_metros(x1) * self._escala, convertir_a_metros(y1) * self._escala) for (x1, y1) in self.puntos]
        self._cuerpo.fixtures[0].shape.vertices = box2d.b2PolygonShape(
            vertices = self.vertices).vertices