Editing Solids and Surfaces - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 204

Several useful options are available for this command:
• planar Object : The cutting plane is defined by a planar object to be se-
lected, such as a circle, an ellipse, an arc, a 2D spline, or a 2D polyline.
• Surface : This is the only option that allows you to specify a non-planar
cutting object. The selected surface must intersect the whole object to be
sliced.
• Zaxis : The cutting plane is defined by a point on that plane and a second
point that specifies the normal to the plane.
• View : The cutting plane is parallel to the current view that passes through
a point to be specified.
• XY / YZ / ZX : The cutting plane is parallel to the XY, YZ, or ZX plane that
passes through a point to be specified.