The world of animation seems to have no boundaries and it is not a thought of twenty-first century. Already at the beginning of last century, animation has started an interaction with the live world. One of the first live action / animated films was Gertie the dinosaur (1914) by Winsor McCay, the pioneer of early cartoons. Created Brontosaur firstly was used during McCay’s vaudeville performances and finally recorded on tape. There was some kind of dialogue between a man and an animal, the specific interaction. Winsor gave her some instructions which she done in a tricky way. In the end, McCay disappeared behind the screen just as a cartoon version of him climbed onto Gertie’s head and rode off. It was the mix of creations which gave inspirations for future animations.
Twenty-six years later, when sound film has been already known, Warner Bros. Made a cartoon called You ought to be in pictures, directed by Friz Freleng. It pictured the moment when cartoon characters (Porky Pig & Daffy Duck) entered to a real world. Producer Leon Schlesinger appeared as himself going into dialogue with cartoons. In 1994 it was voted #34 of the 50 Greatest Cartoons of all time by members of the animation field.
Technological success was for sure Space Jam from 1996. Here, cartoons and live characters played fully on an equal footing mixing animated and real world. That was probably the reason of its box officce success, grossing over $230 million worldwide.
There were several ways to make this kind of movies. From double-printing two negatives onto the same release print, through optical printers or aerial image animation cameras or using rotoscoping. Nowadays, in a digital era, this trick are often in use but animations could be so realistic that human eye can receive it as real, non-cartoony appearance.