Vtk.js: Convert the selection point into world coordinates

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.

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

Can anyone please help me?