What is time step factor and critical time step in thermal simulation


In thermal simulation set up, what are parameters 'time step factor' and 'critical time step'?


Have you found an answer to your question already? If not, I would encourage you to read the corresponding sections in Sim4Life's user manual:
2.8.2 Thermal Simulation Settings Numerical Stability (this is in the FDTD section, but the same criteria apply in the thermal solver)