Troubleshoot assigning objects to Render Layers through the Relationship editor

User Guide > Rendering and Render Setup > Rendering > Visualize and render images > Visualize scenes and render images > Troubleshooting Rendering >

Assigning objects to Render Layers via the Relationship editor is not recommended since you may inadvertently assign an object without it's transform. Instead, use the Render Layer editor to assign objects to layers.