TRISO calculates temperatures and heat flows at complex component interfaces and thermal bridges. Model data is input by entering parameters or by tracing a graphical template. The resulting models can be calculated in 2 or 3 dimensions. Program users can define boundary conditions in the form of adiabatic connections, temperatures and heat sources that are constant, as well as temperatures and heat sources that vary over time. The graphical output allows the user to make interactive changes to the direction of view, as well as to the depicted component sections and displayed simulation variables.