Well.. See I get what your saying and understand that'd take a very, very long time. Unless of course, I had knowledge of programmeing and made something to do it for me..
I figured I could just export the height map, alpha maps, texture maps, as an image, then rotate the image 180 degrees and import it back into Tallis or FuTa, but neither seem to be working. Oh. I think one of the programs, exports a .height file?.. Which I've never heard of, and google isn't bring any help either, and on the page I believe it was FuTa, there's no description on what to do with it.. lol I just thought that was funny.
Yes, export .height files! Then... do what?