# Insane pdb output

**URL:** <https://gromacs.bioexcel.eu/t/insane-pdb-output/13791>\
**Category:** User discussions\
**Created:** [October 25, 2026, 4:12pm UTC](https://gromacs.bioexcel.eu/t/insane-pdb-output/13791 "2026-10-25T16:12:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Vini161](https://avatars.discourse-cdn.com/v4/letter/v/2bfe46/32.png) [@Vini161](https://gromacs.bioexcel.eu/u/Vini161)\
**Post date:** [October 25, 2026, 4:12pm UTC](https://gromacs.bioexcel.eu/t/insane-pdb-output/13791/1 "2026-10-25T16:12:58Z")

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GROMACS version:2024  
GROMACS modification: No

Insane pdb output makes POPG and POPC as POP, as it truncates the name of the bead, does it affect martini3 forcefield, how it recognizes the bead? I need it in pdb for some pre-processing

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**Author:** ![rachelwilson](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@rachelwilson](https://gromacs.bioexcel.eu/u/rachelwilson)\
**Post date:** [October 29, 2026, 10:57am UTC](https://gromacs.bioexcel.eu/t/insane-pdb-output/13791/2 "2026-10-29T10:57:05Z")

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pdb resnames are limited to 3 characters, so POPC and POPG both become POP and can’t be told apart from the pdb alone. if your preprocessing reads resnames, use the .gro output instead, it keeps the full name.