Thanks for quick response. I have checked the simulation and memory report, which indicates 99.6% (20.714 GB) for running simulation. In my structure there is a dummy region (big ring resonator-- inside area of the ring). Is there any way to define a coarse mesh setting for that dummy region (black area in the attached pic) in 3D FDTD?nI attached both the: (i) memory report, (ii) simulation structure.nAny suggestion is highly appreciated.nnn