The goal of prepomax is to develop into a general-purpose pre- and post-processor, and I think it is necessary to support the reading and writing of intermediate grid formats, such as VTK format
This has already been discussed here: Export to *.vtu Format for Paraview
There are existing converters from CalculiX’s .frd to .vtk. Maybe ParaView devs will add support for .frd files in the future, you can vote for this request: CalculiX format native support (.frd) - Feature Requests - ParaView
Thank you for your reply, I know this program, I mean if the future development direction of propremax is to support the pre- and post-processing of various other solvers, I think it is a good way to natively support the reading and writing of vtk