# Separation of velocity and coordinates from trr file

**URL:** <https://gromacs.bioexcel.eu/t/separation-of-velocity-and-coordinates-from-trr-file/594>\
**Category:** User discussions\
**Created:** [July 29, 2020, 5:31am UTC](https://gromacs.bioexcel.eu/t/separation-of-velocity-and-coordinates-from-trr-file/594 "2020-07-29T05:31:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Santanu](https://avatars.discourse-cdn.com/v4/letter/s/6a8cbe/32.png) [@Santanu](https://gromacs.bioexcel.eu/u/Santanu)\
**Post date:** [July 29, 2020, 5:31am UTC](https://gromacs.bioexcel.eu/t/separation-of-velocity-and-coordinates-from-trr-file/594/1 "2020-07-29T05:31:36Z")

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GROMACS version: 5.1.5  
Hi everyone, I want to generate dcd and veldcd from trr file for some analysis. As per my knowledge, trr file contain both coordinates and velocity information. So can you please help me to seperate velocity from coordinates. Also , please help me if there are any flags available for writing velocity and coordinates in two different trr file during simulation. Regards Santanu

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**Author:** ![Masrul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/masrul/32/234_2.png) [@Masrul](https://gromacs.bioexcel.eu/u/Masrul)\
**Post date:** [July 30, 2020, 2:39am UTC](https://gromacs.bioexcel.eu/t/separation-of-velocity-and-coordinates-from-trr-file/594/2 "2020-07-30T02:39:42Z")

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MDTraj has a tool called [mdconvert](http://mdtraj.org/1.9.3/mdconvert.html), which converts between different trajectory formats. You might find it useful.

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**Author:** ![Santanu](https://avatars.discourse-cdn.com/v4/letter/s/6a8cbe/32.png) [@Santanu](https://gromacs.bioexcel.eu/u/Santanu)\
**Post date:** [July 30, 2020, 2:40am UTC](https://gromacs.bioexcel.eu/t/separation-of-velocity-and-coordinates-from-trr-file/594/3 "2020-07-30T02:40:50Z")

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Thank you for your response. I’ll try.