I am trying to solve a 1D, two-phase Stefan problem on Modulus 21.06 and implement the Stefan conditions on a moving boundary. I am solving the 1D, unsteady heat equation with different conductivities on either side of the free boundary as the PDE. For the interface, I implemented a class similar to the DiffusionInterface class as in chapter 9 of the User’s Guide. However, I need to give the Stefan conditions on the moving boundary and cannot implement them because the free boundary changes with time. Can you give me an idea to implement conditions for variable coordinates? Can we use the same approach as the parametric PINN but solve for the coordinate parameter?