# Pbc mol with center not working

**URL:** <https://gromacs.bioexcel.eu/t/pbc-mol-with-center-not-working/11445>\
**Category:** User discussions\
**Tags:** analysis-tools\
**Created:** [February 3, 2025, 3:01pm UTC](https://gromacs.bioexcel.eu/t/pbc-mol-with-center-not-working/11445 "2025-02-03T15:01:38Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![priyabrata](https://avatars.discourse-cdn.com/v4/letter/p/ba8739/32.png) [@priyabrata](https://gromacs.bioexcel.eu/u/priyabrata)\
**Post date:** [February 3, 2025, 3:01pm UTC](https://gromacs.bioexcel.eu/t/pbc-mol-with-center-not-working/11445/1 "2025-02-03T15:01:38Z")

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GROMACS version:2020.4  
GROMACS modification: Yes/No  
Here post your question  
I have selected one lipid from a bilayer and extracted trajectory with one lipid and all solvent molecules then I wanted to make lipid centered but after entering with pbc mol option the bc box and molecules are not aligned, how to solve it.

 ![Screenshot from 2025-02-03 20-27-50](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/4/4771b13a644b891c6d46d8f6fd51e4e43e6eef1a.png)