# How to input platform motions time series and observe the responses.

**URL:** <https://forums.nlr.gov/t/how-to-input-platform-motions-time-series-and-observe-the-responses/2026>\
**Category:** Computer-Aided Engineering Software Tools\
**Created:** [April 24, 2019, 9:42am UTC](https://forums.nlr.gov/t/how-to-input-platform-motions-time-series-and-observe-the-responses/2026 "2019-04-24T09:42:12Z")\
**Posts on this page:** 1\
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**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\
**Post date:** [April 24, 2019, 12:35pm UTC](https://forums.nlr.gov/t/how-to-input-platform-motions-time-series-and-observe-the-responses/2026/2 "2019-04-24T12:35:03Z")

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Dear Danupon,

You cannot directly specify 6-DOF motion of the platform in FAST / OpenFAST without customization of the source code.

For the 3 platform translation modes, you can use FAST v7’s Seismic module to prescribe time histories of motion–please see my post dated Aug 29, 2012 in the forum topic found here for more information: [Software Releases](http://forums.nlr.gov/t/software-releases/522/1).

Related questions have been discussed on this forum e.g.:

> [@Control for scaled-down 5MW NREL](http://forums.nlr.gov/t/control-for-scaled-down-5mw-nrel/1087/1):
>
> Dear All, I am a Polish student (Lodz University of Technology) currently working on my Bachelor Thesis where I analyze a concept of multi-rotor wind turbines for deep off-shore application. The idea behind it is to replace the 5MW NREL wind turbine with a set of 7 smaller rotors (which in total give the same swept area as the baseline turbine), compare their energy production and design appropriate frame. I attempt to use FAST to evaluate performance of an individual rotor of MRWT. I already …

> [@Imposing Estimated Motion to Bottom of the Tower](http://forums.nlr.gov/t/imposing-estimated-motion-to-bottom-of-the-tower/1361/2):
>
> Dear Enes, What you are trying to do sounds similar to what is discussed in the following forum topic: [Regarding Seismic Load by FAST code](http://forums.nlr.gov/t/regarding-seismic-load-by-fast-code/1107/1). I’d recommend against trying to prescribe the motion of the first tower node, which is related to both the platform and tower-mode degrees-of-freedom; instead, I suggest you prescribe the motion of the tower base, which is the platform in FAST. Best regards,

> [@Rigid Wind Turbine with Harmonic Motions](http://forums.nlr.gov/t/rigid-wind-turbine-with-harmonic-motions/685/6):
>
> Dear Sara, I agree with Gerrit that the displacement, velocity, and acceleration of a DOF should not be changed directly without considering whether the equations of motion are consistent with the specified motion. If you simply wish to prescribe a platform surge motion time-history, you can use FAST’s seismic loading module, which was developed for a related purpose. Please see my post dated Aug 29, 2012 in the forum topic found here for more information: [Software Releases](http://forums.nlr.gov/t/software-releases/522/1). Best regards,

Best regards,

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