# how to use "vtkStreamTracer"

**URL:** https://discourse.vtk.org/t/how-to-use-vtkstreamtracer/3389
**Category:** Support
**Created:** [May 25, 2020, 8:49am UTC](https://discourse.vtk.org/t/how-to-use-vtkstreamtracer/3389 "2020-05-25T08:49:09Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![xuexl](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/x/3ec8ea/32.png) [@xuexl](https://discourse.vtk.org/u/xuexl)
#### Post date: [May 25, 2020, 8:49am UTC](https://discourse.vtk.org/t/how-to-use-vtkstreamtracer/3389/1 "2020-05-25T08:49:09Z")

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I have two questions about “vtkStreamTracer”.

One is the data setting by “SetInputConnection”, what is the format of data ? can i create by myself ?

The other is the source setting by “SetSourceConnection”, why need this source? i can not understand.

Best to provide an example, thank you.

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### Author: ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [May 25, 2020, 8:53am UTC](https://discourse.vtk.org/t/how-to-use-vtkstreamtracer/3389/2 "2020-05-25T08:53:42Z")

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[https://lorensen.github.io/VTKExamples/site/Cxx/Visualization/StreamLines/](https://lorensen.github.io/VTKExamples/site/Cxx/Visualization/StreamLines/)

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### Author: ![xuexl](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/x/3ec8ea/32.png) [@xuexl](https://discourse.vtk.org/u/xuexl)
#### Post date: [May 25, 2020, 9:18am UTC](https://discourse.vtk.org/t/how-to-use-vtkstreamtracer/3389/3 "2020-05-25T09:18:59Z")

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Sorry, i download and excute all the examples about "vtkStreamTracer " of vtk, but i still do not understand. and i have readed the description of “vtkStreamTracer”.

I want to read the data file, but the data format is binary(e.g., vtk and bin file), like a black box.

I create a poly line, how to create vector of the poly line ? There is no result of "vtkStreamTracer " now, will it be valid when i create vector ?

And i create a “vtkPointSource” with 100 points, Are every point as the start of streamLines ?

Thank you .

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### Author: ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)
#### Post date: [May 28, 2020, 8:28pm UTC](https://discourse.vtk.org/t/how-to-use-vtkstreamtracer/3389/4 "2020-05-28T20:28:45Z")

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What exactly you don’t understand?