In order to create splits exactly on the rail faces, define Control Points using the CONTROL POINTS> PROJECT [NORMAL] function.
Split the Box at the positions of the created Points. Use the BOXES> SPLIT function and select the created Points with the right mouse button to snap on the Points.
NOTE: Deactivate the flag TANG (TANGENCY) in order not to apply tangency constraints when a split is defined.
Do the same for all the sides of the rail. Also a split must be created in each one of the two planes of symmetry.
