Detect when OpenIGTlink streamed transform no longer updated

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Hi,
I stream tracking data to Slicer via OpenIGTlink, but I would like to be able to detect (i.e. emit an event) when tracking is no longer updated (e.g. the tracked object goes out of range).
I have looked at what methods are available for vtkMRMLLinearTransformNode, but found nothing conclusive.
Thanks
S.

2

You might want to look at the Watchdog module in SlicerIGT. It can monitor any number of nodes, and will trigger a ModifiedEvent on the Watchdog node if their status changes. The status of individual nodes can be checked with vtkMRMLWatchdogNode::GetWatchedNodeUpToDate().

If you’re using Plus, and SendValidTransformsOnly is “FALSE”, then you can check the TransformStatus attribute on the TransformNode which is sent over OpenIGTLink as metadata.

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Since I am indeed using Plus, I opted for the second solution and it works like a charm, thanks !

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