How to make one model node unselectable

when i move the fiducial point, i want to move the point on the suface of the head ,but when close to the tube,the point attach to the tube , is it possible to make the tube unselectable use code?
i understand move the camera can solve these,this scene is a example , i need help to solve these problem use code to make the tube unattachable

You almost answered it yourself, as I think what you need to do is
to make the tube actor not be picked.


thank you pinter
i have written tubeModelNode.SetSelectable(False)
but the when i place the fiducial point in 3D view,the fiducial point still attach the surface of tubeModelNode

I just tried this in Slicer 5.2.1 and if I call SetSelectable(False) on a model node it is not picked by fiducial placement.

i think i need to check my code , than you very much