How can I make filled region react to object shape and size in plan view?

[Pavlin]

Hello all.
I created “Y/N” parameter “Emergency light fitting” (instance one) within my light fitting family and I’d like to get my fitting automatically hatched when value of this parameter is “Yes”. I don’t use any annotation for my light fitting as I’m happy with realistically proportioned rectangular boxes on my drawing, only thing I wish is automatic hatching of “emergency” boxes.
“Filled region” ribbon is not available in model family, only in annotation one. Using annotation family with filled region nested in light fitting family would be ok if I could use view scale as a parameter in order to establish a rule “Filled region dimension = Light fitting dimension * View scale”. As I understand, view scale can’t be used as a parameter in formulas, is that correct? If yes, then what you could recommend me to do to achieve my aim (see above)?
Thanks beforehand.

[Pavlin]

So, it seems, manually operated scale factor instead of "view scale" is the only way. Can anybody advise how can I implement it in formula to control my nested annotaion family's dimensions?

[Steve_Stafford]

I create a detail item family because a filled region is available for those. I make length and width parameters that are instance parameters so they can be stretched easily. I create a filled region that is controlled by length and width.

I nest the detail item into the light fixture family. I align and lock the ends of the detail item to the light fixture's reference planes so its size controls the instance parameters of the detail item. Then I create a yes/no parameter in the host family that I can use to control the Visible parameter of the nested detail item.

If the light fixtures dimensions are changed the detail item follows suit and I only have to check the emergency option on/off to show it.

[Pavlin]

This works perfectly. Thank you very much, Steve.