@RobYes, I've checked the relevant section of the UDF manual on DPM parallel computing and it says "In the case of parallel simulations, you must use user variables specific to particles, as they can be accessed via macros TP_USER_REAL(tp, i) (tp is the type of Tracked_Particle *) and PP_USER_REAL( p, i) (p is the type of particle *). Only this information is in partition boundaries, while other local or global variables will not cross partition boundaries." , I have used TP_USER_REAL(tp, i) to save my calculations according to the instructions, but the fluent parallel calculation does not return a "continuous" result for me.