AutoCAD Mechanical enables you to create hidden lines by specifying which objects lie in front of the others. The overlapped areas of the objects that lie behind are drawn as hidden lines. Objects overlapping each other this manner are said to be involved in a “hide situation”.
Any closed contour on a contour layer or a non-mechanical layer can be selected as a foreground object. the AutoCAD Mechanical automatic property management mechanism intelligently ignores objects that are not appropriate for a hide situation; for example, centerlines and hatches.
AutoCAD Mechanical supports two commands for creation of hide situations, AMSHIDE and AM2DHIDE. AMSHIDE command was originally designed for mechanical structure workflows while AM2DHIDE was meant for non-mechanical structure workflows. However, we subsequently enhanced the AMSHIDE command to support non-mechanical structure workflows. AMSHIDE provides greater functionality than AM2DHIDE. Hence we recommend AMSHIDE over AM2DHIDE.