@User @User Problem with trying to compute capacitances and resistances yourself is that foundries don't tell you about all layers that are used in the process, like hard masks, seed layers, etc. So most of the times small lines have a higher resistance than one would expect from the resistivity; fringe capacitances are senstive to exact stack up, ... If one wants accurate value one will need to use the Cadence or Calibre tables as these are measured on produced wafers.