Method for operating a device for additive manufacture of a three-dimensional object

A method for operating a manufacturing device for the additive manufacture of a three-dimensional object by the layered application and selective solidification of a building material in a building area lying in a working surface, the method comprising:

• directing, by a first scanning unit of the manufacturing device, a detection region of a first sensor unit onto at least one first partial region of a test body region without the first scanning unit directing a beam onto the test body region, the first sensor unit being assigned to the first scanning unit,
• irradiating at least part of the test body region with a beam directed onto the test body region by a second scanning unit of the manufacturing device, and
• evaluating measurement signals detected by the first sensor unit,
• wherein the first and second scanning units of the manufacturing device are designed and arranged to direct a beam of a respective first or second beam source controlled by the respective first or second scanning unit onto different target points on the building area, and
• wherein the first scanning unit is configured to direct the detection region of the first sensor unit to a target point of the first scanning unit.