Image Layers (AOVs)

Overview

Using the Image Layers group of attributes the user specifies one or several layers of images to output simultaneously from the rendering process. By default, the Image Layers group of attributes is setup to output only one image layer: the RGBA components representing the main image, also commonly referred to as the Beauty.

It is possible to add any number of layers, each set to output any complementary information to the Beauty image, such as:

• Variables computed inside shaders, commonly called Arbitrary Output Variables (AOVs), such as depth values associated to the Beauty image, original color of surfaces (without the effect of the lighting), the specular and diffuse shading components of the Beauty image. 
• Contribution of individual or group of lights to the Beauty image.

Such layers can be useful for compositors to have many options while composing the final image and/or rapidly establishing the right light balance.

All the layers are rendered simultaneously. Adding many layers do not generally increase rendering time significantly.