While working as a 3D freelancer in Korea, I also work on creating webtoon backgrounds.
(I translated it with Google Translate, so please understand if it's wrong.)
In Korea, most webtoon writers use SketchUp...
SketchUp is easy-to-use and use SketchUp because the lines of the object.
However, because of the working time, there are not many cases where webtoon writers do modeling themselves, and most of them only purchase webtoon backgrounds from the Internet.
However, because modeling is fashionable in popular genres,
Since there are many cases where they do not have a particular genre, webtoon writers often create their own.