SoClipPlane(3) on Linux
The text a660833e7050, as Debian 7 (Wheezy) shipped it.
The SoClipPlane class is a node type for specifying clipping planes. A scene graph without any SoClipPlane nodes uses six clipping planes to define the viewing frustum: top, bottom, left, right, near and far. If you want extra clipping planes for 'slicing' the visible geometry, you can do that by using nodes of this type. Geometry on the back side of the clipping plane is clipped away.