Inception
The film’s director is old-fashioned and preferred using practical effects whenever possible, meaning real-life effects performed physically rather than compute-generated effects. However, it’s not always possible, after all, we’re only humans and our physical abilities are, sadly, limited.

To meet him half-way, they created models and then computerized them when necessary, such as for the ‘limbo city’ at the end of the film. Some special effects can only be created using CGI.