1. A method for determining a layer orientation for a 2D layer image to be generated from 3D image data of an anatomical object in a body of a patient, wherein the method comprises: selecting from a model pool a model resembling the anatomical object imaged in the 3D image data, the model having been assigned a default orientation in a permanently selected relative position with respect to the model; while maintaining the relative position, aligning the model with the 3D image data in order to match the model to the object with maximum coincidence; and selecting the default orientation established relative to the 3D image data as the layer orientation for the 3D image data.