Ceiling/Face-based families

[dbaldacchino]

So I'm getting into the swing of creating some ceiling based families and am finding issues with them. Basically I want to create ceiling-based families that have a plan representation. I know this has been discussed before.

At first I thought something changed drastically in 2009, but I went back to 2008 and the behavior is very similar. The Ref. Level in the family does not adhere to the hosting level in the project. So if I add a model line from the ceiling face (or ref. plane) and lock one end here and the other to the Ref. Level, when the family is inserted in the project and the hosting surface elevation is varied, that model line doesn't flex. It stays the same length as in the family. In 2009, if you lock to the ref. level and the ceiling/ref. plane, it seems that the ref. level becomes the ceiling plane (goes upwards) instead of downwards towards the floor.

So essentially if this behavior doesn't work as one expects, it seems impossible to create a plan representation of a fixture that is overhead, such as a projector. I tried a face-based family, but it doesn't get any better because I can't "flex" the model line vertically (the ref. level in the family will become your workplane surface in the project and has nothing to do with the horizontal level you place your walls on). All I'm trying to do is get a symbolic plan representation if the family is intersected by my project view's cut plane.

If this is true, I might just abandon hosted families altogether and do a regular workplane/level hosted family and specify the equipment vertical offset through an instance parameter. Ugly, but works. Any thoughts/experiences? Thanks!

[jeffh]

Sometimes when creatinga ceiling based family it helps to include an "invisible" model line from the ceiling level down to the reference level. This will insure the family gets "cut". If the family is cut you should be able to display the object in plan etc...

[dbaldacchino]

That's exactly what I'm trying to do but it's not working properly. The model line does not flex when the ceiling is moved up or down. I'll post an example shortly.

[dbaldacchino]

Here's an example.

a) To work properly, the geometry has to be placed on the ref. plane called "ceiling". If you try host it to the ceiling face by setting it as your workplane, the geometry actually moves ABOVE the ceiling. Edit the family and see how I pushed the ceiling down, yet the family hosts perfectly fine on the ceiling in the project.

b) Note how the model line, even though it is locked to the Ref. level in the family, the length stays at 8'-0" (whatever the distance between the ceiling ref. plane and the ref. level is), regardless of the distance in the project between the ceiling and the hosting level.

[dbaldacchino]

No comments about this issue? I can't be the first one to run into this!

[sbrown]

Yes I have run into this issue and have found no great workarounds. the face based is awesome for placement, awful for plan representation. The only solid workaround is a non hosted family, the problem as you know with the non hosted will be that it doesn't cut the ceiling. I think a support request with specific examples will be needed.

Ceilings in general are due for sum updating. I'm tired of having to create 4 sep ceilings to put a ceiling on a hipped roof. Yes you can do it with a roof, but the ceiling hosted items don't host...

[dbaldacchino]

Thanks a lot Scott, that's the feedback I was looking for. I came across a family that someone told me worked fine in 2008 and not in 2009, but after starting a family from scratch in 2008 to understand how this type of family behaves, I see little difference. The family in question never really worked correctly, even in 2008. There IS a slight difference in the way things behave when geometry is locked to the ref. level between 2008 and 2009, but nothing results in any advantage. I'll file a SR with examples. This will make a good blog post too

[sbrown]

You can make an invisible line with your own ref. planes that you can stretch but then in any view that cuts this line you will see the symbol.

[dbaldacchino]

Correct. You can even just place a dimension with a label and not lock the base of the model line and give it an instance height. So for example if you place a ceiling mounted projector (ceiling based) on a 10'-0' ceiling, you could then type in the ceiling height in this instance parameter and your model line would be as tall as the space. Obviously you only need it to be as high as the cut plane, but you get the point. It'll cut the family and your symbolic representation will show up. The family shouldn't require all this though, as there is a ref. level in the family but it is not behaving as one would expect. If that level conicided with the ceiling host level, it would make the invisible line height automatically adjust with your ceiling height.