Recently I've wanted to get into making a pop-up book for kids and upon my research I've seen it mentioned the pre-production process starting with a paper engineer. Since this question wasn't on the site and I think it falls under the production process I thought it might be an interesting question. What is a paper engineer?
There are a couple of books out there with related titles:
Paper Engineering for Pop-up Books and Cards - by Mark Hiner
Paper Engineering and Pop-ups For Dummies - by Rob Ives
And there is a STEM engineering teaching resource website which has a section on Paper Engineering in the specific context of popups:
And there's a site dedicated to popups in which there are listings for authors & paper engineers:
Which taken in concert lead me to believe that there's a recognised sub-branch of paper engineering which is specific to folding and popup paper products.
hope that helps.