# How trigger consecutive fiducial placements?

**URL:** <https://discourse.slicer.org/t/how-trigger-consecutive-fiducial-placements/17724>\
**Category:** Support\
**Created:** [May 21, 2021, 4:42pm UTC](https://discourse.slicer.org/t/how-trigger-consecutive-fiducial-placements/17724 "2021-05-21T16:42:34Z")\
**Posts on this page:** 2\
**Page:** 1

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**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:** [May 21, 2021, 4:42pm UTC](https://discourse.slicer.org/t/how-trigger-consecutive-fiducial-placements/17724/1 "2021-05-21T16:42:34Z")

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How to trigger the fiducial placement just after the placement of other fiducial nodes and so on?  
I had listened to addNode method like below:

 ![Screenshot from 2021-05-21 22-09-35](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/6/1/6166a883dd9653df570be7adf634e556b6e9f273.png)  
But when I call the addNode method in the script it’s getting into an infinite loop(because of the functions calling each other probably). Even after I commented addNode method its looping for every mouse moment.

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**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:** [May 21, 2021, 4:57pm UTC](https://discourse.slicer.org/t/how-trigger-consecutive-fiducial-placements/17724/2 "2021-05-21T16:57:33Z")

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You only need to create single markups fiducial node. You can add any number of control points to it. To keep placement mode active, enable “persistent” option.

I would recommend to put a [qSlicerMarkupsPlaceWidget](http://apidocs.slicer.org/master/classqSlicerMarkupsPlaceWidget.html) widget on your module GUI to activate/deactivate point placement. It ensures that the correct markups fiducial node is selected, enables/disables placement and persistent option. You can specify persistence by adjusting [placeMultipleMarkups](http://apidocs.slicer.org/master/classqSlicerMarkupsPlaceWidget.html#ab0c8d33893da590b348b9423f13b7bf5) property.