Reporting a dimension without using a reporting parameter

[chughes]

Is it possible to use a parameter like an instance parameter to inform a formula?  I know its telling me I cannot use an instance parameter in a formula, and I cannot use a reporting formula because the needed distance is not hosted.

Working on a shutter assembly.  The shutters contain an array, with the array count driven by a distance formula.

I will control the height of the top and bottom shutters manually and would like to have the middle shutter height adjust dynamically as the overall height is changed.  I cannot make the shutter family height instance based and lock to reference planes, so I need the distance to be reported (like a reporting parameter) and pushed back into a formula to control the middle shutter height.

Below is how it *could* be done, if I had a way to grab the middle distance.

[ToanDN]

Why not: Mid Height = Height - Top Height - Bottom Height?

[bin]

I don’t think it was telling you that you can not use instance parameter in formula. It’s probably telling you that you over-constraint your model. 

[chughes]

Height is an instance parameter.  I could make it a type parameter, I suppose.  I wanted the flexibility of moving it independently of others.

[chughes]

Its not overconstraining.  It's just me trying to force my idea of how something should work on Revit and Revit punching me in the face and reminding me who is boss here. 😄

[Anonymous]

The parameters in the formula need to be the same type - you have a calculation based on a type and instance parameter - make both the same.