It is useful for large scenes, when you work with lot of MetaElems. Example: http://e-learning.vslib.cz/~hnidek/pics/deer.jpg (PildaNovak's model) - shortcuts for hiding of MetaElems: H ......... hide all selected MetaElems Shift-H ... hide all unselected MetaElems Alt-H ..... unhide all hidden MetaElems - items in header menu of 3dview