A method of forming a wrapped article, comprising the steps of: forming a continuous stream of material such as an agricultural product; moving the continuous stream of material along an elongated path; compressing the continuous stream of material to reduce the cross-sectional area thereof until a predetermined cross-sectional dimension is achieved; drawing the compressed continuous stream of material through a rod-forming arrangement, the rod-forming arrangement having a non-contact displacement transducer associated therewith; folding at least one web longitudinally around the compressed continuous stream of material to form a continuous rod of material; and detecting variations in rod density within the rod-forming arrangement from a signal obtained from the non-contact displacement transducer.