Find this section in some selected objects' transform node Attribute Editor.
Use these flags to override your global settings.
Select this option to follow the global settings in the Render Settings window.
Select this option to hide the object in your render.
Use this flag to control the visibility of the selected object.
Use this flag to turn raytracing on or off for the selected object.
Use this flag to enable or disable shadows for the selected object.
Use this flag to enable or disable caustics for the selected object.
Use this flag to enable or disable global illumination for the selected object.
If you are using render proxies to manage your scene, use this option to set your render proxy as renderable so that it is rendered instead of your base geometry.
This is a per instance flag. Therefore, if you have five instances of your base geometry, and you only want to replace three of them with your render proxy, you can use this flag to set the three instances as Renderable.
Render proxies allow for more efficient renders. Using this flag, you can choose not to load and render complex geometry that you do not need in your scene.
For more information regarding render proxies, see Using render proxies in your scene.
Use this option to override your geometry with a mental ray geometry shader or a user defined mental ray shader.