Continuous Linear Lighting Fixture

[bvm76]

I am trying to model a continuous lighting fixture with no preset length. My goal is create an instance parameter to where I can put the length while on the project. I tried to make the "Length" as Instance Parameter but have a problem with the "Emit from Line Length" parameter (can't modify).

Any advise will be much appreciated. 

[Alfredo_Medina · Accepted solution]

Select the light source object and change the default association of the "Emit from line length" property to your "length" instance parameter, instead of the default type parameter.

[curtisridenour]

So, this definitely works. Why does it work? Doesn't this break the rule of an instance parameter cannot drive a type parameter?