Rollover image to view object_id pass (utility shader set to obj)

The aov_write shader in combination with the utility shader is a useful combination for writing out an Object ID pass. This simple setup will allow you to use an ID pass in compositing software to identify certain objects by their color. We will also isolate certain objects and give them specific id's with which to group by color.

Standard Surface

Aov_write_rgb shader

ObjectID added to aov_name of aov_write_rgb shader

Utility shader

Final shader network

Custom AOV

Add a Custom AOV and rename it 'ObjectID' (the same name used for the aov_write_rgb shader)

Utility shader's object mode uses the name of the shapes to compute the color


We can also use the Object ID Color Mode to define individual id's to object's inside a group. For example, currently, all of the windows are grouped together and so render with the same id color. If we want to change the color of one of the window objects, we can repeat the above process but apply it to the first window using a different id number (id 2).

Arnold Properties Modifier added to first window with 'id 2' added to User options