Suggestion: Option to not select backfaces when using selection box.

[simonpaulkeating]

This should only select faces visible to the camera and omit from the selection those that are either facing a different direction or occluded by other faces. Using this from multiple angles it would be easy then to invert the selection to select all interior faces of the object. Note. An additional 'delete interior faces' could be derived from this if the selection from multiple angle was automated.

[JannisX11]

I updated your original issue #2363 to focus on the brush to make it not a duplicate.