Beam Reference Axis
Each Beam possesses a reference axis which serves the precise connection of Beams for clean intersections and establishes hotspots and edges for selecting, moving and transforming Beams. Its direction determines the beam’s “left” and “right” surfaces for the purpose of applying surfaces in the Model Panel of Beam Settings.
The direction of the reference axis follows your cursor as you drag it to draw the beam. (To see the arrow on the beam that indicates the axis direction, turn on View > On-Screen View Options > Walls and Beams Reference Lines.)
In the 3D window, the reference axis of a selected Beam is shown in a separate color: you can change this color using the “Reference Lines in 3D” setting at Options > Work Environment > Selection and Element Information.