# When building a cube with Gmsh, surface labels are automatically added

**URL:** <https://community.freefem.org/t/when-building-a-cube-with-gmsh-surface-labels-are-automatically-added/3534>\
**Category:** General Discussion\
**Created:** [October 6, 2024, 3:23am UTC](https://community.freefem.org/t/when-building-a-cube-with-gmsh-surface-labels-are-automatically-added/3534 "2024-10-06T03:23:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![yongheng](https://avatars.discourse-cdn.com/v4/letter/y/f04885/32.png) [@yongheng](https://community.freefem.org/u/yongheng)\
**Post date:** [October 6, 2024, 3:23am UTC](https://community.freefem.org/t/when-building-a-cube-with-gmsh-surface-labels-are-automatically-added/3534/1 "2024-10-06T03:23:28Z")

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Hi all, When I was trying to create a mesh in Gmsh, while defining a cube, it automatically added a surface label that I already had, which is also in the  
`Surface Loop(29) = {167, 169, 170, 171,176,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25};` segment, it added surface 177, which is the same as my surface 25. When drawing the 3D mesh, the following errors occurred:  
“Error: Invalid boundary mesh (overlapping facets) on surface 25 surface 177”  
“Error: No elements in volume 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33”.  
Why is this happening? Any small suggestions would be greatly appreciated.