How to associate a popup with a vtkActor?

I have several vtkActor(s) on a vktFullScreenRenderWindow that visualize faults in
3D space. I need to link a label popup with each actor but not sure how… thanks

Check out the SpheresAndLabels example for how to associate text with points in your scene.

Thanks for quick respond.

Can I add onclick event on the sphere to display the matching labelWidget?
A related question, how can I fix a labelWidget to window display position instead
of world position?

Trying out with vtkLabelWidget

vtkLabelWidget it’s not from standard VTK collections, right ?

If you want an onclick event, you can either do actor picking with vtkPicker, or you can use widgets. If you want to check out widgets, look for the PolyLineWidget example as a starting point.

It is from vtk-js/Sources/Interaction/Widgets/LabelWidget
I was hoping to get it to stick to a corner like the OrientationMarkerWidget but
failed

If you want a label that sticks to the corner, you can look at using SVG widgets. Check out Sources/Widgets/SVG/SVGLandmarkRepresentation/index.js for an example (the PolyLineWidget example uses this). You can construct arbitrary SVG scenes that can either be associated with 3D points, or independent. Since you want to have the labels be static with respect to the scene, you can use SVG to position your desired text using percentage positions.

I think I have all the pieces I needed. I will try to integrate them. thanks

Got this to work. I used some code fragment from WidgetManager and SVGRepresentation and made a watermark like SVG layer. I would like to be
able to snapshot these SVG layer along with the canvas image captured with renderWindow.captureImages(). Are there usage example ? thanks.