See the Python reference of this logic brick in
The Visibility Actuator allows the user to change the visibility of objects during run-time.
Using the visibility actuator will save on Rasterizer usage, however, not Physics, and so is limited in terms of Level of Detail (LOD). For LOD look at replace mesh, but be aware that the logic required can negate the effect of the LOD.
Toggle checkbox to toggle visibility.
Toggle checkbox to toggle occlusion. Must be initialized from the Physics tab.
Toggle checkbox to toggle recursive setting – will set visibility / occlusion state to all child objects, children of children (recursively).