# Assign label to selected parts of a surface model

**URL:** <https://discourse.slicer.org/t/assign-label-to-selected-parts-of-a-surface-model/18210>\
**Category:** Development\
**Created:** [June 18, 2021, 3:22pm UTC](https://discourse.slicer.org/t/assign-label-to-selected-parts-of-a-surface-model/18210 "2021-06-18T15:22:19Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Aep93](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/aep93/32/5990_2.png) [@Aep93](https://discourse.slicer.org/u/Aep93)\
**Post date:** [June 18, 2021, 3:22pm UTC](https://discourse.slicer.org/t/assign-label-to-selected-parts-of-a-surface-model/18210/1 "2021-06-18T15:22:19Z")

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Hello all,  
I have a surface model (.vtk format). I want to choose some of the elements of this model (interactively) and assign a different label to them. How can I do this?

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/1/a/1ac40cb87a0bb9513cce244c005c0794dbd87674.png)

Thanks in advance

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [June 18, 2021, 8:25pm UTC](https://discourse.slicer.org/t/assign-label-to-selected-parts-of-a-surface-model/18210/2 "2021-06-18T20:25:00Z")

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You can select individual cells as shown [here](https://slicer.readthedocs.io/en/latest/developer_guide/script_repository.html#select-cells-of-a-model-using-markups-fiducial-points). You can also select entire regions by placing a closed curve on the surface, as shown in the beginning of this video:

[![](https://img.youtube.com/vi/nLva95ZF4ko/maxresdefault.jpg "Extract one side of a closed surface mesh") ](https://www.youtube.com/watch?v=nLva95ZF4ko)