Auto Restrain (Underground)
The Auto Restrain (Underground) 
option is a convenient shortcut for automatically applying default restraint boundary conditions on the external boundary for underground models. When the Auto Restrain (Underground) option is selected, the entire external boundary will be automatically assigned XYZ restraints (i.e. all surfaces, edges, and vertices of the external boundary will be fully restrained in all directions).
This option is primarily applicable for underground excavation models.
To apply auto restraints to an underground model:
- Select the Restraints workflow tab
- Select Auto Restrain (Underground) from the toolbar, the Restraints menu, or the Right-click menu and restraints will be automatically applied, as described above.