This paper introduces a model based detection approach for typical structures in the agricultural environment. In contrast to other existing approaches in this area it exclusively relies on distance data information generated by a laser scanner which makes the detection robust against varying illumination. Additionally, the method was designed to be easily adaptable to different agricultural structures as well as to minimize computation power. To test the performance and the capabilities of the presented approach a prototypical baling assistance system was implemented where a tractor had to follow a straw windrow while the implement created round bales.