Rendering a world position pass with Arnold

You can use the Arnold_Point AOV to create a world position pass (an AOV is the Arnold equivalent of a render channel). Here’s the Arnold_Point render channel in the render region:

A world position pass (aka a position map), is an image where each pixel’s R, G, B colour values represent the x, y, z coordinates of the corresponding vertex, in 3D world space.

If you loaded the rendered position map into the FxTree, or Composite, you can see that the RGB values correspond to the XYZ position coordinates: