# Send single Fiducial- OpenIGTLink

**URL:** <https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397>\
**Category:** Support\
**Created:** [July 3, 2019, 3:56pm UTC](https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397 "2019-07-03T15:56:16Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![ChiaraTe](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/chiarate/32/4100_2.png) [@ChiaraTe](https://discourse.slicer.org/u/ChiaraTe)\
**Post date:** [July 3, 2019, 3:56pm UTC](https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397/1 "2019-07-03T15:56:16Z")

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Hi,  
I am writing an User Interface with Python Qt and SlicerDesigner and I am using OpenIGTLink for communication with external device.  
I send the whole Fiducial List with :  
connectorNode.RegisterOutgoingMRMLNode(FiducialList), but can I send only one fiducial of the list?

I don’t know how to access the position of the single fiducial and send it as VTK object.

Thank you

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**Author:** ![Sunderlandkyl](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sunderlandkyl/32/79987_2.png) [@Sunderlandkyl](https://discourse.slicer.org/u/Sunderlandkyl)\
**Post date:** [July 3, 2019, 7:37pm UTC](https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397/2 "2019-07-03T19:37:33Z")

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Which version of Slicer are you using?

In Slicer \<= 4.8.1 OpenIGTLinkIF had the ability to send/receive points using a vtkMRMLMarkupsFiducialNode.

The current version of OpenIGTLink in Slicer does not currently support point messages.

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<div class="post-metadata">

**Author:** ![ChiaraTe](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/chiarate/32/4100_2.png) [@ChiaraTe](https://discourse.slicer.org/u/ChiaraTe)\
**Post date:** [July 3, 2019, 8:08pm UTC](https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397/3 "2019-07-03T20:08:16Z")

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I noticed this problem with Slicer 4.10.  
In 4.8 I can send points with OpenigtlinkIF but all the points of the markupsList. For example if I have a fiducialList with three points: p0,p1,p2 how can I send only p2?

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**Author:** ![Sunderlandkyl](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sunderlandkyl/32/79987_2.png) [@Sunderlandkyl](https://discourse.slicer.org/u/Sunderlandkyl)\
**Post date:** [July 3, 2019, 8:26pm UTC](https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397/4 "2019-07-03T20:26:12Z")

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Looking at the implementation of the old OpenIGTLinkIF, it doesn’t look like it’s possible.

You could implement a workaround by attaching an observer to the fiducial node and sending the position as a transform message for the time being.

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<div class="post-metadata">

**Author:** ![Sunderlandkyl](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sunderlandkyl/32/79987_2.png) [@Sunderlandkyl](https://discourse.slicer.org/u/Sunderlandkyl)\
**Post date:** [July 3, 2019, 8:41pm UTC](https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397/5 "2019-07-03T20:41:30Z")

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I see you’ve already commented on it but for the sake of others, here is the SlicerOpenIGTLink issue on GitHub:

> <https://github.com/openigtlink/SlicerOpenIGTLink/issues/67>

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<div class="post-metadata">

**Author:** ![ChiaraTe](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/chiarate/32/4100_2.png) [@ChiaraTe](https://discourse.slicer.org/u/ChiaraTe)\
**Post date:** [July 8, 2019, 1:23pm UTC](https://discourse.slicer.org/t/send-single-fiducial-openigtlink/7397/6 "2019-07-08T13:23:56Z")

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Hi,  
I have solved putting each fiducial in a new list where there is only that point.  
Thank you