Originally Posted by
dkoch
I can not claim to understand all of the nuances of structural members, as I rarely need more than those created by the wizard. But if I recall, because structural members can be oriented vertically (columns), horizontally (beams/girders) or at an angle (braces), the XYZ coordinate system used to define the members is not the World Coordinate System, but is an Object Coordinate System. I believe that the X axis is along the length of the member. You are on your own for which directions are Y and Z. I would guess that Y is the member depth ("d"), parallel to the web of a W-shape, and Z is the member width ("bf"), parallel to the flanges of a W-shape, but I could be wrong about that.
As for your custom blocks showning on all styles, that sounds like you are editing the drawing default display settings, rather than setting a style-level override and editing that, so that the display changes only affect structural members of that style. When editing the member style display settings, be certain that, for the desired Display Representation, there is a checkmark in the toggle in the right column, and the source indicates that it is a style override, not drawing default.