The above is 2 of the many inlets(blue) and outlets(red) that I have in my case. They green is fluid domain of certain length. Essentially I want my massflowrate of outlet in red assigned to massflowrate for the next inlet in blue. (mdot at Outlet1 = mdot at Inlet2 kind of arrangement)nSo I hook the above udf to all the ids, i.e. ID 10, 11, 12, and 13. With the ID!=10000 condition picking only 1 of the four ID (I think), and ready to calculate the area averaged mass flow rate.nif it is any other id, then mdot is 0.nand then F_Profile to the thread nAnd no, Dynamic thread would not be helpful here, as the tubes are static and this is just 2D.n