A comprehensive understanding of rockfall trajectories is the key to effectively control rockfall hazards. An important characteristic that distinguishes different rockfall models is the presentation of the rock block in the model. Lumped mass models represent rock as a dimensionless point while rigid body models can consider block geometry in rockfall simulations. The potential blocks of the Mardin Castle are selected to study the differences between the lumped mass and the rigid body simulations. The trajectories of the lumped mass model are exactly the same for any size of blocks while rigid body models generate different rockfall paths and bounce height and run out distance accordingly. Increase in block size and non-circularity, cause large divergence between lumped mass and rigid body models. More reliable and conservative protection measures can be designed according to the rigid body simulations.