why do some families have " offset from Host" parameter and some don't?

[HVAC-Novice]

I'm using R2024 and have some (created from previous versions) face-based families that have the " Offset from Host" and some don't. the only clue I have is this article that states in R2020 Revit changed how that parameter is called. My example here are light fixture families that I want to suspend from the host (a ceiling, or roof, or wall). i also have a tag that shows the "elevation from level", which is important to the contractor. 

I attached 3 families:

- " EL_Interior..Lithonia_CLX"  has the native " offset from host"  and all is fine. My tag also shows the correct elevation. This was created some years before R2024 and upgraded

- " EL_Strut"  also is a few years old, but does NOT have that native " offset from host" parameter. I created a fake instance parameter called " offset from host - fake" and added a plane to attach the extrusion to to suspend the fixture from the host. the problem with this workaround is, my tag shows the height of the host, not the actually suspended fixture. I assume the "Elevation from Level" uses the actual host in the family.

- " offset_test" is a family I created to day in R2024 from the generic face-hosted family (and then converted to lighting fixture - this is what i usually do to create face-hosted families from scratch). I really hoped this comes with the native " offset from host" parameter, but it doesn't.

I've been struggling and wondering for years, and usually added my fake parameter and the new offset-plane. Obviously my hack doesn't work with the tag that shows the actual elevation. So i really want to understand how to do it " the right way" . 

Can someone enlighten me? 

My only hack i can think of is to use the one family that has that parameter, and base new families on that. But that can't be the solution. I think i need some education on how this parameter works 

- what determines if a family has that " offset from host" parameter?

- how can i add or enable tha tin a family that doesn't ahve it? Or how do i create a new family and ensure it has that parameter? 

[HVAC-Novice]

I still don't have a solution besides re-creating that Strut family from scratch. 

it looks like in R2020 the old "Offset" and "Elevation" parameters got replaced with new "Offset from Host" and "Elevation from Lev... I assume my strut family must have been on an old family and must have lost that ability. Maybe an issue converting from 2019 to newer format. Who knows. 

Is there any way to add that native "Offset from Host" parameter? If not, re-building the family seems to be my only option if I want to show proper elevation from level with the tag. I could use the spot elevation, though. But that seems like a hack. 

[aleksa.mandic]

I am encountering the same issue. Two different face based families one has built in Offset from Host parameter and another one does not. 
Ofc there is a way to add some offset parameter but what is happening to this built in one.

Any answers to this topic?

[Simon_Weel]

Did some testing. If I create a new Family using template 'Electrical Fixture.rft' - Offset from Host is there. If I use template 'Generic Model.rft' and change the Family Category to Lighting Fixture, Offset from Host is there too. 

[HVAC-Novice]

For families that don't have that parameter, I ended up creating a new reference plane that gets controlled by a new "Offset from Host" parameter I create. I put the geometry on that plane. 

[aleksa.mandic]

Yes, when you create family from electrical fixture template it has offset from host parameter, but it is not face based.
For example, the family "M_Clean Receptacle" I attached is face based, and it has offset from host parameter. 
The family "M_Electrical equipment..." is face based too, but without that parameter.

Even if i put completely the same settings (category, part type, etc..) to both families, still one will have that parameter and one don't.