Marco
I tested your example and got the result you described with both xvi and pdf outputs.
I think you have found the transition defined by ‘vthreshold’.
From the Therion Book…
“
vthreshold <number> <units> ◃ threshold for interpreting LRUD readings as left-right-front-back reading perpendicular to the shot.
If passeges are horizontal (inclination < vthreshold), LR is perpendicular to the shot and UD is vertical.
If passages are more or less vertical (inclination > vthreshold), even UD becomes perpendicular to the shot – otherwise passages would not look very good. In the case of vertical shots, UD is interpreted as north-south dimension from the station to allow tube-like modelling of verticals
“
I had thought the default value of vthreshold was 60 degrees, but it seems it may be around 67.5 degrees.
Bruce
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