Particle Orientation from H5 file

Andrew Greeley
Andrew Greeley Altair Community Member
edited August 2022 in Community Q&A

I am trying to use a simulation .h5 file to reconstruct a set of particles from one simulation in another simulation. The position, velocity, etc. are self explanatory and match the inputs in the createParticle method in the custom factory API. For orientation however, the .h5 file contains four numbers that define the orientation and EDEM and the custom factory API use a 3x3 matrix to define the orientation. How do I use the 4 provided values to get the required 9 values?

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Best Answer

  • Stephen Cole
    Stephen Cole
    Altair Employee
    edited July 2021 Answer ✓

    Hi Andrew,

     

    The h5 file stores the orientation information as a quaternion and the custom factory API is looking for an orientation matrix.  if you export the data from the EDEM Analyst this will export the orientation in the format that the factory requires (you have to choose 9 queries, xx, xy, xz orientation etc.).


    To read direct from the h5 file you would have to convert the quaternions - https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation

    Regards

    Stephen

Answers

  • Stephen Cole
    Stephen Cole
    Altair Employee
    edited July 2021 Answer ✓

    Hi Andrew,

     

    The h5 file stores the orientation information as a quaternion and the custom factory API is looking for an orientation matrix.  if you export the data from the EDEM Analyst this will export the orientation in the format that the factory requires (you have to choose 9 queries, xx, xy, xz orientation etc.).


    To read direct from the h5 file you would have to convert the quaternions - https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation

    Regards

    Stephen

  • Saeed Naamnh
    Saeed Naamnh Altair Community Member
    edited August 2022

    Hi 

     

    I am wodering about the type of orientation matrix that Edem uses for particle orientation, is it Euler matrix or quaternion matrix. 

    See the pic 

    image