A method determines position data of a platform at a plate of an additive manufacturing device, having scanner optics for scanning a laser. The plate has holes that receive a holder, marks on the plate, and receptors for receiving laser target parts. A first position dataset is obtained with a position of a holder inserted in a hole with respect to the marks. After mounting the plate and inserting the platform into the holder, a laser mark is marked on the laser target parts using the laser at laser mark positions in the scanner optics' coordinate system. A pre-manufacturing image of the support plate is acquired with the laser marks on the laser target parts. A second position dataset having positions of the marks with respect to the laser marks is obtained from the pre-manufacturing image. The position data is determined from the position datasets and the laser mark positions.