I have a cube that is scaled about 10 times on the Z axis. I added a plane, rotated it 45 degrees on the Y axis, and placed it just below the top of the cube. I applied a boolean difference modifier to the cube, and it cut off the bottom. How can I invert the boolean operation to cut off the top of the cube instead? The plane should be deleted after the cutting.

Plane and cube shown without boolean modifier

Plane and cube shown with boolean modifier cutting off the wrong part of cube

  • $\begingroup$ it depends on the face normals, flip the plane 180° and try again $\endgroup$
    – Chebhou
    Mar 25, 2015 at 23:34
  • $\begingroup$ You can flip normals on the plane to fix that. $\endgroup$
    – Denis
    Mar 25, 2015 at 23:34
  • $\begingroup$ related: blender.stackexchange.com/a/50632/1853 $\endgroup$
    – user1853
    Apr 26, 2016 at 18:42

2 Answers 2


The Boolean modifier calculations depends on the face normals to decide what's inside and outside ; for a simple plane case the face normal is the local z_axis so it's enough to flip the plane 180°

for other case :

  • enter edit mode hit Ctrl+N
  • check inside option on the tools panel
  • 1
    $\begingroup$ Also note that you can use Ctrl Shift N to enable the inside option without an extra step $\endgroup$
    – gandalf3
    Jul 10, 2015 at 18:52

you can use a different kind of operation on the boolean modifier for different results: enter image description here


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