Light Fixtures & Interference

[sfaust]

I was going through an interference check for th first time since we upgraded to 2009, and I got a TON of interferences between light fixtures and ceilings.

Through a little investigation, it seems that Revit is including the light source definition (the yellow piece in the family) as a solid when checking for interference. Obviously this is not a real object and shouldn't be checked for interference, so is this a known issue? Is there a way around it?

Thanks,
Steve

[Justin Marchiel]

i could see this as being a good point to check if you needed to do rendering or export to lighting programs. it could tell you if something would be blocking the light and giving false reading.

sorry i dont have an answer to your question.

Justin

[sfaust]

perhaps, but it can really get in the way too. for example we have a 2x4 troffer which is set to area light, half projection (down only). The light source definition covers the area of the light and then extends out a foot or two. So any time a light fixture gets close to a wall it shows an interference. This could actually be helpful if you could set the distance, but as far as I'm aware you can't. Also if there happens to be a column close to the light fixture... What about wall sconces?

Anyway, we can just ignore the interferences, so it's not that big of a deal, but it makes a lot more data to sort through unnecessarily, so it would be nice to be able to turn it off...

[sfaust]

ok, I did some more checking and found out that you CAN change the size of the light source definition. It's a family parameter called "Light Source Symbol Size". This changes how far out from the light this symbol will go. Unfortunately it can't be set to 0, but it can be set to 1/4" or something for tight situations.

I'd still like it to be a seperate category on interference checks, so we could see if it was too close to a wall for good lighting, or actually overlapping the fixture.

Regardless, this makes it a much more useful tool!

[mwiggins121466]

Try turning it off. It is a category of the light fixture. Not sure if it will skip it if it is off.

[sfaust]

it is off. That category is always off by default. Also, on or off is a view specific setting, interference check is for the whole model, regardless of what is visible in the view.

[mitch.cornelius]

I ran into this same problem...here's what I posted on the Navisworks forum thread:

As an update, I found a way to get them out of the revit model all together...i'm just not sure what adverse effects this may have

1.Select a light fixture
2.Click “Edit Family” on options bar
3.Click Settings > Family Category and Parameters
4.Uncheck the box next to “Light Source”
5.Load family back into project

[sfaust]

have you tried rendering after this? I would guess it might kill the ability to have it emit light...

[mitch.cornelius]

Luckily, I don't need renderings...but I guess that would be the main problem.

[sfaust]

fair enough. But changing the size of the light fixture per my above post works pretty well I've found...

[mitch.cornelius]

I didn't see where to select the size of the light source, do you have a screenshot?

[sfaust]

See attached. In type properties

[mitch.cornelius]

Right under my nose...thanks.