# Integration Time

**URL:** https://discourse.vtk.org/t/integration-time/5009
**Category:** Support
**Created:** [January 14, 2021, 5:05pm UTC](https://discourse.vtk.org/t/integration-time/5009 "2021-01-14T17:05:31Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![mcgoldba](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mcgoldba/32/2849_2.png) [@mcgoldba](https://discourse.vtk.org/u/mcgoldba)
#### Post date: [January 14, 2021, 5:05pm UTC](https://discourse.vtk.org/t/integration-time/5009/1 "2021-01-14T17:05:31Z")

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Hi All,

I am curious about the “Integration Time” variable that is available after generating a vtkStreamline. I understand that this is some measure of the age of the streamline, but what are the units here, and how is this variable calculated? The values I get for seem to be too large to be in seconds, but maybe I am wrong about this.

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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: [January 15, 2021, 11:48am UTC](https://discourse.vtk.org/t/integration-time/5009/2 "2021-01-15T11:48:10Z")

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The integration time is derived from the velocity computed by the vtkInterpolatedVelocityField:  
[https://vtk.org/doc/nightly/html/classvtkInterpolatedVelocityField.html](https://vtk.org/doc/nightly/html/classvtkInterpolatedVelocityField.html)

The unit then depends on the unit of the Vectors in use for integration.