I have an object which I have created using three boolean diff operations. I want to top-align it to a surface, but it always behaves as if the top of the object is at a distance from itself. In other words, when I top-align this object, it doesn't actually align.

Is there some invisible clipping going on that the top-align function is not taking in to account?




The object is labelled by the blue arrow, while the edge I am trying to top-align it to is labelled by the red arrow. I use the "Front" view to top-align, but I'm showing the 3D view since it's easier to see what I'm trying to accomplish there.