Cutting with Boolean Modifiers I have a scene where I need to be able to "interactively" cut a mesh.  I have set up a bounding box, and the object I need to cut is set inside.  When I move the vertices of the bounding box, the object is cut because of my implementation of a boolean modifier with the "union" property.  Here is an example:



However, the sphere is just being flattened in this image.  What I need is to be able to literally "cut" the sphere, so that it is hollow on the inside.  Is this possible, and how can I do it?

Here is how I want it to look, but with the ability to be animated.



Any help/suggestion is welcomed!

Edit:  I added a photo of how I want the image to look.
You could add a solidify modifier to the sphere before the boolean modifier:



Also note that you can set the boolean modifier to Difference and use a plane as the Object, it may be easier to animate than a cube.

For this to work, the normal of the plane must be facing the sphere:



You can flip the direction of the normals by


Pressing Flip Direction in 3D view > Tool Shelf (N) > Basic > Normals
Pressing CtrlN and enabling Inside in the Redo menu (either at the bottom of the Tool Shelf, or by pressing F6).


Result: