If you want to farm this it takes about 10 minutes.
In Chapter 3, you'll get to your first inanimate object. It's a gate that jitters and you have to go up on a hill and turn a search light onto it after you start a generator. This is not the farming place but the farm is directly after this as you go down the stairs after destroying this gate. You'll get your checkpoint as you go down the stairs. There is flashlight to pick up on your right and two gate pieces to destroy with it. Pick up the flashlight, destroy the two gate pieces, and restart the last checkpoint. This puts you at the top of the stairs and you can do this 9 more times for a total of 10 to get the 20 inanimate objects you need for the achievement.