As a side project of mine, I have been working on a power delivery network simulator for KiCad. It uses the finite element method to solve the Laplace's equation on the PCB's copper geometry, computing the voltage drop and current density across the entire board.

The idea is simple: you annotate your schematic with special text directives that indicate which pads are power sources and which are current sinks and resistors and so on. Then, padne extracts the copper geometry together with the annotations, building a FEM mesh and solving the equations.

The results are visualized by an interactive GUI that can show both voltage drop and current density.

The project, with more up to date information, can be found in its GitHub repository.