Provide more information about nozzle element, WRC-297 and Bijlaard L1 and L2 field requirements in AutoPIPE?
Is it important L1 and L2 direction in the meaning that nozzle could be near the top or bottom?.
Open the Nozzle element dialog and look at help for L1:
L1 Enter the distance from the center of the nozzle to either vessel end or to the face of the nearest internal stiffening attachment (e.g., ring).
L2 Enter the distance to the other end of the vessel (or nearest internal stiffening attachment in that direction).
As one can see, it does not matter which direction L1 or L2 are in, the most important information would be that the distance from the center of the nozzle in both directions to the nearest stiffening ring; top ring or bottom ring. Again, the direction is not important for L1 and L2, distance is important.