Hello,
I tried to make a .xvi for elevation and extended section starting from this dataset:

survey test
  centerline
    units compass degrees
    units clino degrees
    units tape metres
    data normal from to length compass clino     left        right    up      down
    0 1 10   45  -67        [1 2]         [3 4]          [5 6]          [7 8] 
  endcenterline
endsurvey

everything looks good, the up and down data are plotted in the right way.

Then I changed the clino to -68 degrees and noticed that vertical sections were rotated in the elevation and extended xvi. Is that correct? Am I missing something?

Here's the thconfig:

encoding  utf-8
source dati.th

export map -proj plan      -o pianta.xvi
export map -proj extended  -o sezione.xvi
export map -proj elevation -o elevazione.xvi


Thanks,
Marco