This node is very useful for creating the /composing the 3D scene with a 2D background or may be useful when creating a video footage for the blender.
3d objects are being shown using this node, this node o also shows the image which has been set up at the background., this also enables the back buffer.
What are the compositing sockets in the render layer node ?
Lets see it in details:
Z: distance from the camera (away direction)in the blender usints.
Normal(NOR):when the lights are coming from the sight then how color is affected.
UV: How the image is distorted by the mapped mapping of the UV.
Speed(Vec):This is for the speed of moving object ,it mainly for fast moving object and at which direction the object is moving.
Color(Col):This is for the RGB value s of the color of an image.
Diffuse: The softening c of colors as they diffuse through the m materials
Specular: how the colors will shine when they are added or exposed to the light
Shadow: This is for objects on another object because one object create shadow on another object .
AO: This gives the effect of ambient occlusion on the colors
Reflect(Ref):This is an object and the type of the object are mirror type. This mirror type objects show colors by reflection. This is not the part of the color of the basic material.
Refract: This is the bending of colors when they are passed through objects which are transparent.
Radio(Radiosity):Objects can emit the colors and cast onto the scene.
Index of each object have some numeric ordinal(index) o in the scene when seen by camera.