The XDMF file is just a “meta-data” file to describe to ParaView what is actually stored in the .dream3d file. The .dream3d is just a standard HDF5 file with a different extension.
You can read the .dream3d file directly into DREAM3D-NX and use basically the same 2 filters that are in DREAM.3D version 6.5.171. I guess I would need to know exactly what kind of VTK file that Ansys needs. If you have an example VTK file that Ansys reads could you pass that along. Even if it is from their documentation, that would give me something to go on.
Detail: VTK file can contain both regular grid geometry and data where the grid is described by Origin, Resolution and dimensions OR it can contain geometry data such as a triangle surface mesh or poly lines. Neither DREAM.3D nor DREAM3D-NX can output the “triangle” style of VTK files.
Hope this explanation helps.