...
XClip properties provide added control for how xclips are displayed. 
Display only result: if this option is unchecked the clipping boundary will be ignored, and all of the geometry of the clipped blocks or xrefs will be displayed.
Enable front clip: If this option is selected the xclip will clip everything in the clipped entities above a specified height. Front clipping always occurs parallel to the original clip boundary.
Front Clip: Sets the height for front clipping.
Enable back clip: If this option is selected the xclip will clip everything in the clipped entities below a specified height. Front clipping always occurs parallel to the original clip boundary.
Back Clip: Sets the depth for back clipping.
In the following picture the the xclip has a Front Clip of 12in. and a Back Clip of 1in. 