It is possible to change the DXF background in a Netsys Pipe or Duct sizing project.
Ensure the project is backed up before attempting these steps
Ensure that the new DXF is set up so that your floors align correctly. Examine the new DXF in your CAD software and ensure that it and the DXF to be replaced have:
Then, to import the updated DXF:
When the floor opens, it will contain the new DXF file.