# Double Filter Revit model to obtain List of Elements

**URL:** <https://forum.dynamobim.com/t/double-filter-revit-model-to-obtain-list-of-elements/93393>\
**Category:** Revit\
**Created:** [September 1, 2023, 5:12am UTC](https://forum.dynamobim.com/t/double-filter-revit-model-to-obtain-list-of-elements/93393 "2023-09-01T05:12:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![claracoutoCD8EP](https://avatars.discourse-cdn.com/v4/letter/c/cc9497/32.png) [@claracoutoCD8EP](https://forum.dynamobim.com/u/claracoutoCD8EP)\
**Post date:** [September 1, 2023, 5:12am UTC](https://forum.dynamobim.com/t/double-filter-revit-model-to-obtain-list-of-elements/93393/1 "2023-09-01T05:12:50Z")

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Hi,

I’m trying to create a Dynamo script that filters my Revit model twice in order to obtain a List of Elements, to use as input in the Element.SetParameterByName node.

The first filter is By Category, and then I intend to filter the elements within that category by the value of a parameter.

Has anyone tried doing this before?!

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**Author:** ![denisyukj](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/denisyukj/32/166182_2.png) [@denisyukj](https://forum.dynamobim.com/u/denisyukj)\
**Post date:** [September 1, 2023, 6:22am UTC](https://forum.dynamobim.com/t/double-filter-revit-model-to-obtain-list-of-elements/93393/2 "2023-09-01T06:22:54Z")

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Hi, @claracoutoCD8EP  
The script is filtering selected mechanical instances and defined value of ‘Mark’ parameter. Pay attention that it is valid only for instance parameter. What kind of parameter have you chose for filtering?

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/d/9/d91e96fc5298ae9646458b334d385a34b632f4d8.png)

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<div class="post-metadata">

**Author:** ![claracoutoCD8EP](https://avatars.discourse-cdn.com/v4/letter/c/cc9497/32.png) [@claracoutoCD8EP](https://forum.dynamobim.com/u/claracoutoCD8EP)\
**Post date:** [September 1, 2023, 9:55am UTC](https://forum.dynamobim.com/t/double-filter-revit-model-to-obtain-list-of-elements/93393/3 "2023-09-01T09:55:19Z")

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Hi, @denisyukj

It’s an instance Parameter.

Thank you so much for you help.