Why are there no lateral deflections after running a gravity design?

Within the Home ribbon tab > Settings> Design options - General page, there is a check box entitled "Fix column nodes horizontally".   

This settingis also found in Model settings via the Design ribbon tab > Options - General > Gravity Design.  The setting must be changed here for existing models.

If this option is checked then column nodes will be restrained from moving laterally when a Design (Gravity) command is run.

The reason for this option is that the Engineer may wish to obtain preliminary sizing of elements under gravity loadings but is not yet ready to add a lateral stability system to the model.

However the setting should not generally be used for models containing trusses, especially roof trusses, as spreading of the trusses will be prevented and results will not be correct.

Note that nodes attached to a diaphragm are not automatically contrained by this option since this would be an illegal constraint to the diaphragm.