In order to allow for the shading effect of surrounding objects, enter the Average Height and Average Distance that the Facade is from any large object facing your selected Façade.
Note: this button only displays when one Façade is selected. It does not appear if several Facades are selected (since they may have different orientations and the surrounding object may not affect different Facades/Surfaces to the same extent). Facades may also have the same orientation but exist on different planes and therefore, this feature applies to single Facades/Surfaces only.
Note: The Surrounding Buildings feature will only apply when an entire Façade is selected (when a single Surface or only a few Surfaces (not all) are chosen, this feature will not be available since a shading object cannot affect a only a single Surface or Surfaces on different orientations in the same way).