Cut straight lines with knife tool How can I get the knife tool to snap to the same spot on another edge to get a straight cut. Here is an example of what I want to do:



When the line turns green the cut is straight. How can I do this in blender? I have tried using the magnet snapping tool but could not get it to work.
Press C while in knife mode to enable Angle Constrain.
Note that it snaps to angles relative to the view. For cuts on faces which are not aligned to any axis, you can:

Press ShiftNumpad 7 to align the view to the face

Press K to enter knife mode, then C to enable Angle Constrain: