I am trying to make a through hole using inward extrusion. I enterd into edit mode, then I drawed an outline of my hole using knife tool.
then I turn into wireframe shading, rotate my view an select snap to faces and then extrude the hole outline inward
so the hole is created successfully, but I still have a face at the hole bottom. I can select this face separately
But If I try to delete it, I siply delete this face (I can't select it anymore after deleteting), but I do not see through hole, so the basic cube face is still here. So how to remove the hole bottom?