The solution of the heat conduction equation is an unsteady process therefore the time step and duration must be specified.

The physical time step in seconds is specified in the Time step box. The solution process continues until it reaches the final cycle time, the Total time.

Two time stepping schemes are provided in C3D: for example, Constant and Automatic modes. The Constant mode employs a constant time step throughout the simulation whereas with the Automatic option, the optimal time step is computed in each element from the rate of heat conduction and the element size. With the Automatic option, the Maximum time step sets an upper bound on the automatic time step to ensure that fast transients can still be captured with a reasonable temporal resolution.