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dysart
2009-07-02, 03:40 PM
Lighting Fixture Ceiling Based Families from Revit's Product Library seem to have an odd
Height Parameter called " Drop From Ceiling".

At first glance, one expects this to be the distance from a ceiling to the bottom of the fixture.
If one has 8' ceilings and places the lighting fixture with a default 7' "Drop From Ceiling",
one then concludes, oh, that's Revit's way of saying 'Above Finish Floor'. Wrong.

Through design changes, the ceiling gets moved to 12' and the lights want to remain at 7' above finish floor. The user checks the section view and realizes that there is no relationship to the floor level. So now that "Drop From Ceiling" needs to be changed to something. If one increase the "drop" the fixture moves up! Then one realizes that the number needs to be 3' "Drop From Ceiling" to have a 7' Above finish floor light.
A parameter tied to an unseen level is way too obtuse.

I'm modifying my fixtures to have that "Drop From Ceiling" parameter to be a distance from the bottom of fixture to the ceiling. If I design a 12' ceiling and want it to have lights at 7' aff
then the "Drop From Ceiling" will be 5' - isn't that a lot easier? Shouldn't the generic lighting fixtures from Revit be revisited to make them more coherent? Am I missing something?

It would be great to have a ceiling based family that could maintain pendants at the ceiling heights and have an above finish floor parameter tied to the level the ceiling is related to.
This would allow one to modify the ceiling height and maintain the bottom of fixture level.
Has anyone sucessfully made such a family?

dysart
2009-07-02, 09:01 PM
It looks like only a few of the standard Revit Lighting Fixtures have the problem described above. The "Pendant Light - Linear - 1 Lamp.rfa and Pendant Light - Linear - 2 Lamp.rfa"
families have this parameter set incorrectly. The other similar families such as "Pendant Light - Hemisphere.rfa" have the parameter correctly controlling the light position from the ceiling.

The problematic Linear families should be corrected, as they are commonly used as generic fixtures by many architects.

dysart
2009-08-01, 03:01 PM
The factory already corrected previously incorrectly located "drop from ceiling" parameter, with the 2010 release.

Thanks guys...