Hi there,
Well, there are dozens of solutions here,
I'll organize them by the most preferable,
1- Simply edit the type of the lightning fixture, duplicate and give it a name like off "Something"
inside the edit type dialog, scrol down till you find initial intensity, then just give it a zero (0) to any of the input units of lightning power measurement,
and of course make sure that the type has the "Self illumination" material un-assigned, so it does not light up from it,
In this case, you would have a created type that simply doesn't light up.
2- To add a visibility parameter, open the lightning fixture family, then in the proporties disable light source, this will remove the built in light source of your family
Then go to new > family > lightning fixture
It will give you a ball of light, (Lightsource), do your things and put your settings in it, and load it into your lightning fixture,
You can sure drive parameters from editing the type of the loaded light source into the original family, and in this method, you can simply add a visibility parameter from the proproties of the loaded light ball (light source)
BUT YOU WILL ALSO HAVE TO DISABLE THE SELF-ILLUMINATION MATERIAL (WHICH WILL REQUIRE CREATING A TYPE)
3- While placing the lights, in the option bar, you will see light group,
Create a new one and name it, "Powered down" group for example,
And just add the wanted fixtures into this group,
Then when you are in rendering dialog,
Bellow the scheme button in the lightning area, you will see a huge button "Artificial lights" simply untick the one that is associated with the group you created and named "Powered down"
BUT YOU WILL ALSO HAVE TO DISABLE THE SELF-ILLUMINATION MATERIAL (WHICH WILL REQUIRE CREATING A TYPE)
4- Just add a piece of geometry that you can enable or disable it from a visibility dialog that hides the source in it, "Simple extrusion will do the job"
It will be like a switch for turning it on or off,
While ON, it will hide the source, While OFF, it will not hide the source as it would be disabled, (If you didn't get this one just reply)
BUT YOU WILL ALSO HAVE TO DISABLE THE SELF-ILLUMINATION MATERIAL (WHICH WILL REQUIRE CREATING A TYPE)
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Bottom line,
As you noticed above, I would prefer number 1 solution,
Because all the other solution will require you to remove the self-illumination material,
While solution number 1, IS REMOVING THE MATERIAL AND THE POWER OF LIGHT SOURCE
I have placed all the above solutions for educational purposes, they might be handy in other situations too,
Greetings,
Karam