Expression cannot be evaluated - Property Manger

[tjmillar]

I want to label an empty opening with the Header to Wall Top dimension. That figure is available in the info box under Sill or Header Height, but not as a figure I can use in a label. 

In Property Manager, when I try to create a property to display this figure so that I can use it in a label, I use Data Type "Length", select "Expression", and add the "Header Height to Wall Top" parameter from the "Opening" group. When I click Evaluate, I get "Expression cannot be evaluated for this element". Even though Archicad does evaluate this figure in the info box. 

Any suggestions as to what I'm doing wrong?

[poco2013]

Most likely, you have not classified it properly

[tjmillar]

It is classified as an opening. I have experimented with various classifications, and when it is classified incorrectly the error message says that the parameter is not available for that classification, not that it cannot be evaluated. 

[poco2013]

If your using the evaluate function, perhaps you have the wall selected rather than the opening

[tjmillar]

The opening is selected. You cannot evaluate the expression otherwise. If you select the wall, the classification is wrong and you get a "Property is not available for this Element's Classification" error.

[poco2013]

If you have classified the expression for "all elements" or for both "walls" and "empty openings" you will get that message. The opening expression should be classified as "empty opening" only Then select the opening

[Rajesh Patil]

If you are applying "Opening" elements parameter to "Empty Door" parameter it wont work as these are two different elements.

 

[tjmillar]

Thank you Rajesh, that is the issue. I was using Rectangular Door Opening 25, and applying a parameter from the Opening group. Changing the classification to Opening or Empty Opening (or anything else) doesn't fix that issue. If I create an Opening with the Opening tool instead of an empty opening with the door tool the property works. 

So how do I create a label that returns the figure I can see in the Info Box? (Header to Wall top) There are no parameters in the Window/Door group that relate to the wall height, but again, it is a simple option to display that figure in the info box. I just need to be able to put that figure into a label. 

I could use the opening tool instead of the rectangular door opening, but it's not as versatile and I would prefer not to have to resort to that. 

[Yves]

Hi,
With two formulas, one for doors and one for openings

 

 

[tjmillar]

Thanks for your response Yves. I'm sorry but I can't see how that helps. If I use an opening rather than an empty door there is no problem, I can apply the parameter I need (header to wall top - though will need to convert if from a negative to a positive figure for the label). But I want that figure for an empty door, and unlike the list of parameters for openings, there are no parameters for doors and windows that relate to the height of the wall.