Flatten
Modify > Flatten
Description:
The Flatten command (Modify > Flatten) will take
whatever your selection is and scale it by a factor of zero in the
direction specified in the flatten options dialog (Modify > Flatten > ...).
In this dialog you can choose the local (manipulator) x, y, or z axis,
the world-coordinate x, y, or z axis, or the selection's normal
vector. For example, if you have a face that is non-planar and
you want to make it planar, you can select it with the the manipulator
set to orient itself to the face normal (Selection > Auto Orient Manipulator
> To Normal), and then call Flatten with the options set to
flatten along the local y axis.
- Flatten will
work on instances.