Improvements in the Graphical User Interface (GUI) of the 3D rockfall trajectory simulation software Rockyfor3D have been implemented on demand of the many users. The current version (Rockyfor3D v5.2.1) allows a “rapid automatic simulation”, which only requires a Digital Elevation Model as input. All parameters related to surface roughness and elasticity are calculated automatically, using pessimistic values. The new GUI also allows defining directly the form and the dimensions of the blocks to be simulated. Errors related to directory paths containing spaces have been fixed. The algorithms for calculating the rockfall kinematics have not been changed. All members can download Rockyfor3D v5.2.1 from the tools section of our website (after login).