In the Family Editor, click Create tab
Draw panel
Major Segment.
Use the Major Segment tool to select one segment of the rebar shape that will maintain its general position in rotation and auto-expansion behaviors. A major segment adjusts its length to compensate the host, but its orientation within the shape remains unchanged.
Tip: All similar shapes should have the same Major Segment. This ensures they remain in the same position during a shape change.
When selected, the major segment appears tagged with two parallel lines when viewed in the Rebar Shape editor.
Tip: Create symmetrical shapes about the center reference lines in a sketch.