The Ohmmeter of PCB-Investigator Physics enables you to calculate the net resistance and voltage drop between any two points of a net on the PCB.
To use the Ohmmeter, you have to define following parameters first:
In most cases calculations run much faster on graphic cards (GPU) than they do on the universal processor (CPU) (from our experience up to 10x faster). But that depends strongly on hardware properties. GPU is only available for recent Nvidia graphic cards with at least CUDA 5.x support. The graphic card should also have at least 2 GB of RAM, better would be 4 or 8 GB.
The solution requires a large set of nodes inside the PCB volume. Define the spacing in x-y-directions. Standard means a spacing of 0.2 mm, fine 0.1 mm and very fine 0.075 mm. Especially current-carrying traces (only those) need to have at least one, better two, nodes across width. For example the thinnest trace of interest is 0.2 mm wide, then choose at least a raster of 0.15 mm. better take 0.1 mm: The finer the raster, the more computational work. The vertical spacing is defined by the layer stack-up.
Here you have to define the different materials per layer and the general layer stack-up parameters, especially layer heights.
You can find more details here.