Hey @kturnbull,
thx for your help, I added a forum post in the FEA / Solid mechanics section: Connecting domain parts in FE analyses
Right now the volume information of part volumes is not provided in the workbench. It would be easy to add that in the event log for example. But I think a better approach would be to add a heat source boundary condition where we calculate the corresponding W/m³ value before the simulation automatically. Thus we would take that step away from the user as we have the information about the mesh volume parts anyways. We do something similar with force boundary conditions in the mechanical solver. What do you think?