I've got issues with a duct/shroud that I am trying to print and getting it to be solid. I've tried changing everything from infill density to bumping the wall thickness way up. I am wondering if maybe some model manipulation is necessary but have not had any luck yet with that either.
In addition, the interior area I want to be solid is filling with my support material (PVA). Which won't work for me as the shroud will be submerged for end use.
My 3mf for the print is attached, along with a few sequence shots (starting with 1, ending with 5) showing what I am talking about.