# Overwriting project parameters for some elements

**URL:** <https://forum.dynamobim.com/t/overwriting-project-parameters-for-some-elements/15083>\
**Category:** Revit\
**Created:** [September 25, 2017, 12:09pm UTC](https://forum.dynamobim.com/t/overwriting-project-parameters-for-some-elements/15083 "2017-09-25T12:09:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![A.W.A](https://avatars.discourse-cdn.com/v4/letter/a/f0a364/32.png) [@A.W.A](https://forum.dynamobim.com/u/A.W.A)\
**Post date:** [September 25, 2017, 12:09pm UTC](https://forum.dynamobim.com/t/overwriting-project-parameters-for-some-elements/15083/1 "2017-09-25T12:09:12Z")

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Hello!

I’ve been trying to create a new parameter for my floor elements. I can do this just fine, but if I run the script again, another set of project parameters is added to the elements. I need it to simply overwrite these parameters, unless they’ve been assigned a value.

I tried by adding a 4th parameter with a checkbox, to be able to filter out elements which does not have this box checked. The idea is, you fill the three other parameters and then check the box so that there is an easy way of telling whether or not the element has been assigned values. Filtering out the elements is easy enough, however the node only takes in a category as input to create parameters, and not single elements.

Does anyone have a way of working around this?

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/f/6/f6249934841cf5b5539d5d9e5c9fe9d2bfb5b5ac.png)  
Thank you! 🙂

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<div class="post-metadata">

**Author:** ![jacob.small](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/jacob.small/32/161030_2.png) [@jacob.small](https://forum.dynamobim.com/u/jacob.small)\
**Post date:** [September 25, 2017, 1:36pm UTC](https://forum.dynamobim.com/t/overwriting-project-parameters-for-some-elements/15083/2 "2017-09-25T13:36:17Z")

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If statements can be used to only assign a new value when the condition isn’t yet assigned. I’m out of the office so this might not be perfect but it is a start:

```
A==""? A.SetParameterByName("ParameterName",NewValue):
A

```