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I have an oval I am trying to slice two sides from. I select the oval, I add boolean, I select the cube, I select difference and it slices the opposite of what I want leaving me 2 skinny strips and NOT the sliced oval. I've used boolean many times with correct results.. except this time!!

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Marc
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    Related - http://blender.stackexchange.com/questions/7298/why-is-it-important-to-apply-transformation. Transforms aren't applied. As I understand you'd like the oval shaped mesh to have 2 slices across it ? – Mr Zak Feb 05 '16 at 20:45
  • I thought I did that. But to be sure I just did it again -- I added the transforms to all three pieces and tried the boolean difference operation again. SAME thing. I re-uploaded the blend file to reflect that attempt. – Marc Feb 05 '16 at 20:53
  • The desired outcome is to have that main oval cut into 4 oval sections, minus the 2 rectangles – Marc Feb 05 '16 at 21:10
  • I'm not sure how to get 4 oval sections with 2 cutters, but in this case Boolean isn't working as expected because after applying transforms you end up with flipped normals on both cutters (thin cubes). Beware also that they aren't one object, hence they won't cut mesh together – Mr Zak Feb 05 '16 at 21:25
  • Then what's a solution? How do I "flip the normals" to make it cut the dang oval into 4 pieces? I realize the the cutters aren't one object. I was just going to do 2 boolean operations -- Because when I join the cutters to be one object and try the boolean I still get the same result – Marc Feb 05 '16 at 21:28
  • To recalculate normals in Edit mode select faces which have them flipped (in case of your thin objects - all), and press Ctrl+N. Note that using this shortcut in Object mode will indeed result in reloading start-up file. – Mr Zak Feb 05 '16 at 22:41

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First select both of the objects you are going to use to cut, and join them as a single object (CtrlJ:

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Then set the boolean to intersect:

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To see the results you can move the cutting object to a separate layer or hide it.

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Just for fun, here are the other possible booleans with these two objects:

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    You could use Difference as it's always used in these cases, but recalculating those thin objects' normals first. – Mr Zak Feb 05 '16 at 21:26
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    Indeed, the normals on the cutting objects are wrong!. In edit mode you can recalculate them (ctrl+N) and the difference worlks... :) http://i.stack.imgur.com/avM8g.png –  Feb 05 '16 at 21:32
  • You have to be in edit mode –  Feb 05 '16 at 23:22