i just found an interesting new project at GitHub, is a patch for CalculiX to VTK output formats. did not try yet, since i’m not expert in deployment.
CalculiX has many supported mesh format to export (e.g Nastran, Code_Aster, etc) but none for another output results format. even a few exporter available out there, still may useful if done inside CalculiX.
hope it will be officially supported for the next future release.