Hey,
I answered Frank already in a direct message, but just to let you know in the secret of the CDI Reader …
Initially it was developed to only support ICON netCDF data, which is somewhat similar to MPAS. Meanwhile we extended the reader quite a bit and now support also a number of other unstructured weather/climate models with whatever shaped cells. Unfortunately, we have not yet checked the code back to ParaView master, but it is on our list. As Ken pointed out, if you have any issues with it, or want/need to use it, please contact us at DKRZ.
Thanks and Cheers, Niklas