# How to use vtk observer mechanism to change qt widgets?

**URL:** <https://discourse.slicer.org/t/how-to-use-vtk-observer-mechanism-to-change-qt-widgets/14178>\
**Category:** Support\
**Created:** [October 21, 2020, 8:16am UTC](https://discourse.slicer.org/t/how-to-use-vtk-observer-mechanism-to-change-qt-widgets/14178 "2020-10-21T08:16:06Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Chintha\_Siva\_Prasad](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/chintha_siva_prasad/32/7766_2.png) [@Chintha\_Siva\_Prasad](https://discourse.slicer.org/u/Chintha_Siva_Prasad)\
**Post date:** [October 21, 2020, 8:16am UTC](https://discourse.slicer.org/t/how-to-use-vtk-observer-mechanism-to-change-qt-widgets/14178/1 "2020-10-21T08:16:06Z")

</div>

How can I use vtk observer mechanism to change qt widgets? I tried with signals/slots mechanism. But the change in widgets was choppy.