The BackSurface property determines the type of surface used for the +Z direction of a part. When two parts’ faces are placed next to each other, they may create a joint between them. If set to Motor, the
/BasePart/BackSurfaceInput determines how a motor joint should behave.
Most SurfaceTypes render a texture on the part face if the
/BasePart/Material is set to Plastic. Some SurfaceTypes - Hinge, Motor and SteppingMotor - will render a 3D adornment instead. If this property is selected in the Properties window, it will be highlighted in the game world similar to that of a
Show All SurfaceTypes
This code sample shows what each SurfaceType looks like on a part. In addition, it creates a BillboardGui label on the part with a TextLabel that reflects the name of the current SurfaceType.