Viewport Features

In this menu there are many configurable features of 3d viewport.

Smoothing	Smoothing angle and method of smoothing for solid render mode.
Materials	Use materials. If not checked, default gray material will be used
Textures	Use Textures. Overwise, textures will be ignored.
Show Back-Facing Polygons	Enable drawing of polygons that are determined to be facing away from the camera. Most often this options should be disabled, and this will be a performance optimization that avoids drawing polygons that represent back face of part. In normal situtation, these polygons are covererd by front facing polygons
Shadows	Enable real-time shadows. FinalMesh supports shadows from multiple lights of many types using shadow mapping algorithm. Properties of shadow from eacjh lighht is configurable in the properties of light.
Global Bounding Box	Display whole scene bounding box
World Axis	Diplay sceme axis. Shape, Size and position can be configured in options of Viewport.
Bones	Show bones objects.
Lights	Show lights.
Cameras	Show cameras.
Motion Path	Show motion path of selected object.
Show Weights	Show weights of selected object.
Show Normals	Show per vertex normals of selected object.
NURBS Surface & Trim Curves	Show NURBS trim curves and CV grid for selected object.
X-Ray	Show objects in X-Ray mode. X-Ray mode can be configured in options of Viewport.