This is a 2016 stop-motion animation film created by Laika, directed and produced by Travis Knight.  When the film first came out the majority of people thought it was a CGI creation, due to how smooth the animation was and how complex the characters were.

Here is a 'making of' clip showing the painstakingly slow process of stop-motion animation.  You can see the characters being moved bit by bit, being photographed between each movement.

So next time you watch a stop-motion animation you'll be able to understand the process and have an even greater appreciation for it.

Thoughts by,