Pushed a topic removing the usage of m_SliceNode.
See https://github.com/jcfr/Slicer/tree/2664-fix-fiducial-placement

After reverting all the commits of Jim and myself, adding ruler widget in the threed view leads to a crash.

It seems the Ruler widget never worked if there are threeD view. It should probably be split into two widgets:

• vtkAnnotationRulerWidget
• vtkAnnotationRulerWidget2D

There is function named "CreateDefaultRepresentation3D" that is called from nowhere.

A fix to prevent a crash would be to not register the ruler displayable manager with the threeD view.

After reverting the commit of Julien, Ruler widget works ! Currently investigating.

re note 66624 which commit did you revert?

The digging that I'm doing is showing that I'm only getting 3d representations during the crashes, they're created manually in the displayable manager. The main problem to me seems to be that the Is2DDisplayableManager check is failing and the safe downcasts are assuming a 2d/3d viewer that's not correct.

I've got some checks that prevent crashing, but not sure of the base cause yet. Your switch to not using the slice node didn't make a difference?
see svn 21212.

The source of the crash has been discovered.

In vtkAnnotationRulerWidget::CreateDefaultRepresentation(),

the commit of Julien change from:

reinterpret_cast<vtkAnnotationRulerRepresentation*>(this->WidgetRep)->InstantiateHandleRepresentation();

into:

vtkAnnotationRulerRepresentation::SafeDownCast(this->WidgetRep)
->InstantiateHandleRepresentation();

Given the update of Julien, it was then impossible for a vtkAnnotationRulerRepresentation3D to be casted into a vtkAnnotationRulerRepresentation !

Using "reinterpret_cast" was by "great luck" working and the appropriate function was called.

Just looked at your commit and it works because "vtkDistanceRepresentation" is the base class common to both vtkAnnotationRulerRepresentation3D and vtkAnnotationRulerRepresentation.

The problem is that it doesn't fix the 2d/3d check problem, try putting down a fid and a ruler then switching to compare view mode. It crashes in a different place with the representation not being the expected 2d one.

Fixed in r21213 and r21214
See http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&amp;revision=21213
and http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&amp;revision=21214

Simplify code.
See http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&amp;revision=21217

Closing resolved issues that have not been updated in more than 3 months

Fix committed to 1683-launcher-with-output branch.