Abstract: An optical measuring machine includes an optical assembly moveable along an axial direction to acquire an image representing a workpiece, a contactless measuring device connected to the optical assembly to move with it. This contactless measuring device detects a distance between a sensitive portion thereof and a surface of the workpiece. A sensor is configured to detect an angular position around a central axis of a holding assembly, an axial position along the axial direction A control unit activates the optical assembly to acquire a first signal representing an external profile of a measuring zone comprising at first part representing a first tract of the external profile, to activate the contactless measuring device, and to acquire a second signal representing a distance between the sensitive portion and multiple portions of the measuring zone, and to reconstruct the complete geometry of the measuring zone, combining the first and second signals.