Use Home > Prescribed Temperature or Home > Convection Condition or Home > Radiation Condition to apply thermal boundary conditions to your model. In defining boundary conditions for a Thermal model, your goal is to limit the temperature of your model (prescribed temperature), or to limit the heat through your model (convection condition). You can use Home > Constraints > Symmetry to apply a cyclic symmetry boundary condition, which ensures that the temperatures on the edges of the cut are the same. Your model's heat loads and boundary conditions, along with its loads, provide the software with the real-world conditions that it uses as the basis for analysis.