# Area boundaries by wall function
**URL:** https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388
**Category:** Revit
**Created:** [December 6, 2018, 7:44pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388 "2018-12-06T19:44:15Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@arshamm](https://forum.dynamobim.com/u/arshamm)
#### Post date: [December 6, 2018, 7:44pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/1 "2018-12-06T19:44:15Z")
hi,
i’m trying to create the area boundaries based on the function of the wall ( all of them except interior walls )
and i don’t know why this is not working, any ideas?
thanks
the error says ; Warning: Warning: List.FilterByBoolMask operation failed.
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### Author:  [@BenjaminDoty](https://forum.dynamobim.com/u/BenjaminDoty)
#### Post date: [December 6, 2018, 8:00pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/2 "2018-12-06T20:00:33Z")
Have your tried to connect your element collector to the Code Block?
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### Author:  [@arshamm](https://forum.dynamobim.com/u/arshamm)
#### Post date: [December 6, 2018, 8:03pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/3 "2018-12-06T20:03:17Z")
hahaha good one! you got me,
but it is connected and it’s not working.
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### Author:  [@jacob.small](https://forum.dynamobim.com/u/jacob.small)
#### Post date: [December 7, 2018, 5:44pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/4 "2018-12-07T17:44:40Z")
What’s the error when connected?
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### Author:  [@arshamm](https://forum.dynamobim.com/u/arshamm)
#### Post date: [December 8, 2018, 2:14am UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/5 "2018-12-08T02:14:00Z")
> [@arshamm](#):
>
> Warning: List.FilterByBoolMask operation failed.
Warning: List.FilterByBoolMask operation failed.
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### Author:  [@jacob.small](https://forum.dynamobim.com/u/jacob.small)
#### Post date: [December 8, 2018, 4:41am UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/6 "2018-12-08T04:41:55Z")
Connect the code block and check for null values after connecting. My guess is you have a value of null from the get parameter node.
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### Author:  [@arshamm](https://forum.dynamobim.com/u/arshamm)
#### Post date: [December 8, 2018, 4:59pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/7 "2018-12-08T16:59:54Z")
you are right! but this used to work in 1.3 version of dynamo!
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### Author:  [@jacob.small](https://forum.dynamobim.com/u/jacob.small)
#### Post date: [December 8, 2018, 5:03pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/8 "2018-12-08T17:03:12Z")
You sure it had the same nulls?
You can use a second test in the same line to return false for the null values.
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### Author:  [@arshamm](https://forum.dynamobim.com/u/arshamm)
#### Post date: [December 8, 2018, 5:11pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/9 "2018-12-08T17:11:08Z")
i restarted it and now it’s working, this is so stupid! i mean the wall selection part works, i have to leave, sorry, i’ll try it later again, thanks for your help
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### Author:  [@jacob.small](https://forum.dynamobim.com/u/jacob.small)
#### Post date: [December 8, 2018, 5:26pm UTC](https://forum.dynamobim.com/t/area-boundaries-by-wall-function/29388/10 "2018-12-08T17:26:31Z")
FWIW, I recall that the node you are using to get the parameter values, Element.GetParameterValueByName(TypeOrInstance), used to give me fits like this back in the day. I recall thinking it had something to do with worksharing at the time, but I never definitively figured it out.
In this case you know you will always need a type parameter, so you may get better results by pulling the type and getting the parameter value directly from those objects. May help with reliability.