The use of robotics for prefabrication in timber construction is becoming increasingly important. Novel, modular, reconfigurable, and transportable manufacturing systems allow rapid adaptation to project-specific requirements. However, continuous reconfiguration of the system is a major challenge. Accurate calibration is a critical requirement for robotics. Typically, this requires expert knowledge and specialized measurement hardware. This issue arises in specific applications like timber prefabrication, where the availability of robotics experts is limited, and frequent reconfigurations necessitate calibration. To this end, this paper presents a camera-based calibration method for the described use case. The proposed method focuses on automatic calibration without the need for expensive measurement equipment or highly skilled personnel. The proposed method uses AruCo markers to determine the relative pose between the platforms. The automatic calibration process is performed by detecting the AruCo markers in the field of view of the camera of each robot and using them to estimate the pose of the platforms. The experimental results from a simulation evaluate the achievable accuracy and demonstrate the feasibility of the proposed method.