Thank you for your reply. I asked this question because the user manual does not specify the mechanism of force transfer on the Shell element. I would like to implement some custom function via the API, but I can’t start my work due to the lack of this information. I have read ‘DEM Technical Manual’, 'API Solver Manual'and 'Rocky Help 22.1.2'. However, there is no example of a Shell element here. 。･ﾟ･(つд`ﾟ)･ﾟ･ I just want to know how the force is distributed when a contact force is applied to the Shell element. The DEM technical manual says that the force of the Shell element is calculated on the joints connecting the two entities. So I was wondering, if the Shell element is subjected to a contact force, how is this force distributed to the three joints?