Abstract: A control system unit for a 3-dimensional (3D) object manufacturing system is disclosed herein that comprises one or more sensors and a controller. The one or more sensors are to sense 3D-objects manufactured in the manufacturing system in accordance with product specification data and to generate sensor signals representative for the sensed 3D-objects. The controller is to determine 3D-object characteristics of said sensed 3D-objects on the basis of said sensor data signals and to issue one or more corresponding control signals to control a system actuator unit so as to act on said sensed 3D-objects in accordance with their respective determined characteristics. The controller comprises a synthetic sensor data module to generate synthetic sensor data from product specification data of 3D-objects to be manufactured with the object manufacturing system, to therewith simulate sensor data for said 3D-objects to be sensed when manufactured.