Position channel

The Position channel outputs a representation of the position of each point in the image. This is useful for compositing purposes, i.e. when you need to select all the surfaces that are close to the ground floor (to affect them with certain adjustment), or all of them near the camera. Maxwell can measure these positions in either World or Camera coordinates.

Position channel in World coordinates

This mode analyzes the position of each point in the scene in regards to the World coordinates axis and origin.  This information is useful in compositing when you need to perform adjustments dependent on the World position of a surface (i.e. near the ground plane or above other objects to mimic a fog effect, etc). 

The render (left) and the Position channel in World coordinates (right) 

Position channel in Camera coordinates

This mode analyzes the position of each point in the scene regarding the Camera origin and its local axis. This information is useful in compositing when you need to perform adjustments dependent on the Camera position of a surface (i.e. distant objects versus near objects, etc). 

The render (left) and the Position channel in Camera coordinates (right)