Vtk.js: Convert the selection point into world coordinates

Hello,
I used example GeometryViewer to load a VTP file and selected a point using PointPicker , this point is sometimes marked on the back of the selected point. But I want to return the closest point to the surface of the current mouse click, not to the back.

Questions:
Picker class converts world coordinates whether you can set values that return only the selected surface?

Can anyone please help me?