Formula not accepted

[ChristophorosMi]

I want to create a façade system when it is not divided in 4 equal parts. The inner sashes should be longer and the outside sashes should be 85mm shorter by each side. Moreover I would like to giving the width of the family and then the inner and outside sash width distributed autonomously.  My idea of doing that was as it is illustrating in the picture below, however revit is not willing to accept it. Can you please help me sorting this out?

[ToanDN · Accepted solution]

You have circular references.  Try this:

Inner Sash Width = (Width + 170 mm) / 4

[Mike.FORM]

Also you are calling off 'Outter Sash Width' in the formula but your parameter is 'Outside Sash Width'.

Has to be the same name as your warning is stating.