# Draw a fixed sized segment

**URL:** <https://discourse.slicer.org/t/draw-a-fixed-sized-segment/14930>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [December 7, 2020, 10:27pm UTC](https://discourse.slicer.org/t/draw-a-fixed-sized-segment/14930 "2020-12-07T22:27:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![tenzin\_kunkyab](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/tenzin_kunkyab/32/3916_2.png) [@tenzin\_kunkyab](https://discourse.slicer.org/u/tenzin_kunkyab)\
**Post date:** [December 7, 2020, 10:27pm UTC](https://discourse.slicer.org/t/draw-a-fixed-sized-segment/14930/1 "2020-12-07T22:27:58Z")

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Hi Andras,

Is there a way to make a cubic segmentation of size 2 cm by 2 cm by 2 cm (just an example) in terms of its dimension? the symmetric option in scissor effect is not giving me what I need to do.

thank you so much

best  
Tenzin

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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:** [December 8, 2020, 1:22am UTC](https://discourse.slicer.org/t/draw-a-fixed-sized-segment/14930/2 "2020-12-08T01:22:43Z")

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If you want to work with objects of known shape&size then you would normally create a model of it (for a cube you can use `vtkCubeSource`) and import that into the segmentation using `AddSegmentFromClosedSurfaceRepresentation`. See example here: [https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Get\_histogram\_of\_a\_segmented\_region](https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Get_histogram_of_a_segmented_region)