Systems and methods are disclosed for shaping laser light as a line beam for interaction with a film that may have an imperfect, non-planar surface. The system may include a beam stop that defines an edge; a sensor that measures a distance between a selected point on a surface of the film and a reference plane and generates a signal representative of the measured distance; and an actuator coupled to the beam stop and responsive to the signal to move a portion of beam stop edge. Movement of the beam stop edge portion shifts a corresponding portion of the focused line beam in a direction normal to the reference plane to produce a line beam that more closely conforms to the surface profile of the film.