# how to generate multiple mesh files with different time steps

**URL:** <https://discourse.slicer.org/t/how-to-generate-multiple-mesh-files-with-different-time-steps/18596>\
**Category:** VMTK\
**Created:** [July 9, 2021, 2:16am UTC](https://discourse.slicer.org/t/how-to-generate-multiple-mesh-files-with-different-time-steps/18596 "2021-07-09T02:16:15Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![junqiangchen](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/junqiangchen/32/11541_2.png) [@junqiangchen](https://discourse.slicer.org/u/junqiangchen)\
**Post date:** [July 9, 2021, 2:16am UTC](https://discourse.slicer.org/t/how-to-generate-multiple-mesh-files-with-different-time-steps/18596/1 "2021-07-09T02:16:15Z")

</div>

Hi,  
than you for sharing the PARTICLE TRACING example with vmtk,i have problem that how to generate different timestep meshs,can anyone share some example code or tools how to use it generate different timestep meshes?  
best wishes!!  
chenjunqiang

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [July 11, 2021, 3:23pm UTC](https://discourse.slicer.org/t/how-to-generate-multiple-mesh-files-with-different-time-steps/18596/2 "2021-07-11T15:23:19Z")

</div>

See requirements listed [here](http://www.vmtk.org/tutorials/ParticleTracing.html):

> In order to properly compute traces it is mandatory to have _n_ mesh files resulting from a pulsatile cfd simulation. Each mesh file represent a timestep and must have, as a vtkDataArray, 3 velocity components in the axial directions ( usually _u, v_ and _w_ ), or the velocity vector.

---

<div class="post-metadata">

**Author:** ![junqiangchen](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/junqiangchen/32/11541_2.png) [@junqiangchen](https://discourse.slicer.org/u/junqiangchen)\
**Post date:** [July 12, 2021, 1:12am UTC](https://discourse.slicer.org/t/how-to-generate-multiple-mesh-files-with-different-time-steps/18596/3 "2021-07-12T01:12:46Z")

</div>

thanks lassoan,can you share some example how to achieve it?

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [July 12, 2021, 1:32am UTC](https://discourse.slicer.org/t/how-to-generate-multiple-mesh-files-with-different-time-steps/18596/4 "2021-07-12T01:32:58Z")

</div>

You probably need to ask for help on the community forum of the CFD solver that you use.