Hello again all! More problems yet. I have a 3D thermal simulation, which involves a rod split into 11 concentric rings and a heatsink surrounding it, cooling it down to the case below it. I am loading the inner 10 rings at 10W each for a total of 100W, and the base of the heatsink is held at 20C I believe. The 3D simulation runs fine and gives me the "correct" answers. I want to convert it into a 2D simulation so that I can quickly test a number of configuration changes without having to simulate the entire environment. However, when I do that, everything is broken. The thermal flux is too small by a factor of 2, and when I calculate the heat flux through the bottom of the heatsink I get values like 3W, so that the temperatures, etc. are completely wrong. I am baffled as the 3D version of the same thing works just fine. May I ask for someone's time and effort to help me troubleshoot this issue? I have attached the assembly with simulation files for 2D attached. The issue seems to be the "Indium_4MM" piece or "Crystal_11", at which point the heat seems to disappear, although the heatflux at the "crystal" is still too small by a factor of 2: it should be on average 265000 while the simulation gives me an average of 133000. Thanks so much!