A layer orientation is determined for a 2D layer image that is to be generated from 3D image data of an anatomical object in the body of a patient. First, a model resembling the object that is imaged in the 3D image data is selected from a model pool. The model has an assigned default orientation in a permanently selected relative position with respect to the model. While the relative position is being maintained, the model is aligned with the 3D image data so as to match the model to the object with maximum coincidence. The default orientation established relative to the 3D image data is then selected as the layer orientation for the 3D image data.