# Merge each actor descendent in DataPrep: BP loop

**URL:** <https://forums.unrealengine.com/t/merge-each-actor-descendent-in-dataprep-bp-loop/488311>\
**Category:** Blueprint\
**Tags:** Revit, unreal-engine, Blueprint, question\
**Created:** [September 2, 2021, 4:57pm UTC](https://forums.unrealengine.com/t/merge-each-actor-descendent-in-dataprep-bp-loop/488311 "2021-09-02T16:57:30Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![E847](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@E847](https://forums.unrealengine.com/u/E847)\
**Post date:** [September 2, 2021, 4:57pm UTC](https://forums.unrealengine.com/t/merge-each-actor-descendent-in-dataprep-bp-loop/488311/1 "2021-09-02T16:57:30Z")

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Hello,

I am Revit user and I am trying to learn to use DataPrep to import architectural models and make them UE-friendly. I attach working files below.

My goal is to make a BP loop that merges the first Actor’s children to the parent, then the second, the third. Here is a schema.

 ![347871-schema.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/d/28d3126a42f5e53ea556f8ba46429d9719ad68c1.jpeg)

Here the two curtain-wall are made of **196 components** but they are children of only two actors. Yes I could select the actor label and merge it one by one. But in the real project I have over 150 curtain-walls… that’s why I could love to create Custom Dataprep Block (BP) that loop through each actor and merge children. I started this:

 ![347872-bp-testing.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/9/1/6/9169c276d1d3d7efa5d15460f0744d20152b3863.jpeg)

Any help would be greatly appreciated!

[Working files][3]

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**Author:** ![LHawatmeh](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@LHawatmeh](https://forums.unrealengine.com/u/LHawatmeh)\
**Post date:** [February 10, 2022, 4:04pm UTC](https://forums.unrealengine.com/t/merge-each-actor-descendent-in-dataprep-bp-loop/488311/2 "2022-02-10T16:04:01Z")

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hello id like to know if you solved this problem ?

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**Author:** ![E847](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@E847](https://forums.unrealengine.com/u/E847)\
**Post date:** [February 14, 2022, 9:58am UTC](https://forums.unrealengine.com/t/merge-each-actor-descendent-in-dataprep-bp-loop/488311/3 "2022-02-14T09:58:55Z")

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No, not yet.

Using Blender to merge meshes before exporting it via the IFC add-on ([blenderbim.org](http://blenderbim.org)). Then I use DataPrep to add materials and to do easier stuff I know DataPrep can do easily. I think DP will evolve significantly in UE5.

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**Author:** ![sky2017](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@sky2017](https://forums.unrealengine.com/u/sky2017)\
**Post date:** [May 22, 2024, 2:59pm UTC](https://forums.unrealengine.com/t/merge-each-actor-descendent-in-dataprep-bp-loop/488311/4 "2024-05-22T14:59:06Z")

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Hello, I would like to know if you have resolved this issue? I encountered the same problem

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<div class="post-metadata">

**Author:** ![E847](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@E847](https://forums.unrealengine.com/u/E847)\
**Post date:** [October 3, 2024, 2:28pm UTC](https://forums.unrealengine.com/t/merge-each-actor-descendent-in-dataprep-bp-loop/488311/5 "2024-10-03T14:28:29Z")

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Not via DataPrep. I found that it was easier to send the IFC to Blender, work on the geometry and import it. You can easily control how many objects (future Unreal draw calls): I often reduce the number of objects from 80 to 90% with this process.