Yeah, I did work on exactly that,porting a 2 metro ton hydrogen fuel cell CAD model to Ansys. It was a nightmare. You first have to simplify everything by hand

Yeah, I did work on exactly that,porting a 2 metro ton hydrogen fuel cell CAD model to Ansys. It was a nightmare. You first have to simplify everything by hand (aka remove all the small details) and then rework the topology when importing in the FEM tool (modelling supports, junctions etc). This is actually a very active area of research (at least 5 years ago when I worked in simulation). There were papers on voxel methods, Fourier analysis (move the model to the frequency domain and filter out small details that are hard to mesh and affect convergence) to automatically réparé CAD models to an FEM environment :) I have no idea how things have advances since, but it looked nowhere near usable in the industry half a decade ago. Actually, maybe a statistical algorithms would be suited to simplify models should one have a proper dataset to train on, because it's very hard to do analytically.