local coordinate system orientation beta angle reference

[jesosan]

I have a model where columns are sligthly non paralell to global Y axis, and if fact each one has different angles between the x axis local and the X,Y and Z global axis; when you verify in the STAAD.Pro GUI to get a visual representation of the directions the local x and y axes point to they differ up to 180°, that is every column aim local y in extremely different directions, all columns are defined joint i below joint j that is from bottom to up so x axis aim close paralell to Y global. My intention is to define xy local plane parallel to XY global so i've tryed these alternatives: a) By specifying an angle using the BETA command. If i manually adjust the beta angle and verify on GUI i can aproximately orient all columns but its a long process and not an engineering method if you know what i mean. b) Using the REFERENCE POINT method. i define a REFJT a b c MEMB 1 2 3 ... where a b c are the coordinates of a point far away in the direction i want xy local plane, say REFJT 1e+20 0 0 None of these work for me since after specifying the direction all columns keep aiming local y in extremely different directions. Is there a way to know what precise orientation is using STTAD for every column so i can make a spreadsheet or program that calculates the exact BETA value accordingly. I'd like to know the dot product or cross product steps as long as i know STAAD MANUAL states default local coordinate system z local lie in XZ global plane as starting BETA=0. lets express x local axis as (x1 y1 z1) vector calculated as the difereence cordinate to coordinate of starting point and end point, if we eliminate y1 we have the projection of this vector on XZ global plane that is (x1 0 z1), since manual of staad states that local z axis per default lies in XZ global plane we calculate it as the cross product (x1 y1 z1)x(x1 0 z1)=(x2 0 z2). In this point according to the order we take vectors we can obtain 2 opposite directions say: (x2 0 z2) or (-x2 0 -z2), both of them lie on XZ plane and are perpendicular to local x axis. Next step is compute y local axis as the cross product of (x2 0 z2)x(x1 0 z1) or (-x2 0 -z2)x(x1 0 z1); one of these y axis vectors have positive component on Y so i assume this one paired to the z related cross product is the DEFAULT local coordinate system. Question arising is why in my model which has column directions close but no parallel to Y global axis i get all angles (in the plane between y local axis and Y global axis) between x local axis and Y global axis very similar (in fact 88°- 90°) after making a spreadsheet and in STAAD GUI i saw them point in extremely almost 180° directions. Hope somebody can help me. Regards.