Syntax:
set hidden3d set nohidden3d show hidden3d
Hidden line removal may be used for both explicit functions and for explicit data. It now works for parametric surfaces as well. This mode is meaningful only when surfaces are splotted with lines.
When this flag is set, both the hidden portion of the surface and possibly its hidden contours (see set contour) as well as the hidden grid will be removed. Each surface has its hidden parts removed with respect to itself and to other surfaces, if more than one surface is plotted. But contours drawn on the surface (set contour surface) don't seem to work. Labels and arrows are always visible and are unaffected.