Attached is a JPG of what I am going after. If I can get the straight line to work, I can then test if the arc will work.

However, every time I flex the family, only one side stays put and I have to remove constraints in the error window. I am not using a separate nested family ( these are just lines to represent sealant it would be overkill to create a family of just a line ), so I am locking the ends of the first and second arrayed line to the appropriate reference planes. Initially, they also shifted at an angle, but I understand the second array needs to be aligned and locked to the first. I have parameters for the number of copies and the spacing, but when I change the width of the joint, the constraints break and the lines don't flex. I first had to research how to lock and flex arcs, but I can't even get a straight line to flex once it is arrayed.

I have all the reference planes ready, but the line work is not working. I am simply trying to make a Sealant and Backer Rod family that flexes nicely. I have read many posts about parametric arrays and yet it still doesn't work.

Revit parametric