Concrete beams disappear in plan after joining

[kh_jea]

Our office is trying to find a good method for displaying overhead beams in a floorplan. The "detail line trick" AutoDesk proposes only works for level beams, but doesn't work when it is placed on a slope.

I'm trying to use the "Show family pre-cut in plan views" and then have a V&G override on the edges. This works to a certain extent.

When joining 2 beams, the lines disappear. Unjoining doesn't make the beams reappear. Neither does copy. The beams are visible on coarse. Yet in the family itself it's set to always show, regardless of detail level.

There also seems to be a difference between Concrete and Precast Concrete in visibility.

Knowing Autodesk fabulous reputation on consistency, I'm guessing this is a feature and not a bug.

The beams in the screenshot all have the same height and are at the same level. Only the beams that are joined are still visible.

[ToanDN]

Turn on Underlay and set it to look up.

[kh_jea]

But will also show other elements. It may work on some plans/levels, but not all.

I would like to find a method wich works in 90% of the cases.

I would als like to know why the beams behave so unexpectedly.

[ToanDN]

If you nest a shared generic model in the beam family then it should show when located above the cut plane but below the top of the view range.