Auto Restrain External
The Auto Restrain External options are a convenient shortcut for automatically applying default restraint boundary conditions on the external boundary, for underground or surface models.
- Select the Restraints
workflow tab. - Select Auto Restrain External from the toolbar or the Displacements menu and restraints will be automatically applied as described below.
After using these shortcuts you can manually customize the restraints if necessary using the Assign Restraints options (e.g. Restrain X, Restrain Y etc).
Auto Restrain External (underground)
If you select the Auto Restrain Underground 
option, the entire external boundary will be automatically assigned pinned restraints (i.e. all edges and vertices of the external boundary will be fully restrained in the X and Y directions.
This option is primarily applicable for underground excavation models.
Auto Restrain External (surface)
If you select the Auto Restrain Surface 
option, the bottom and sides of the external boundary will be assigned pinned restraints, and the top surface (ground surface) will have no restraints (i.e. free). When using this option, RS2 automatically determines the top surface (ground surface) of the model. If the results are not as expected, you may have to manually assign the desired boundary conditions with the Assign Restraints options (e.g. Restrain X, Restrain Y etc).
This option is intended for surface models with a free ground surface (e.g. slope models).