So much of the emotion and the feeling and the connection from the audience is going to be individual to a degree - and that was the point. How do you get the audience to be emotionally invested in the journey? Maybe some of it is by not being told what's happening all the time.

To me the best movies and the best movie moments draw you in. People want to work for the meal, they just don't want to know that they're doing it. So your job as a filmmaker is to seduce them and entertain them so much that they don't realise that they're working so hard with their brains saying, "Well, this plus this equals this."

The other challenge with WALL-E and EVE is that they don't have faces that you can move around a bunch. Their design is so simplified - with EVE you have two blue dots that you need to use to explore the full range of emotions that a human face can give you. But that's why detail is really important, because all of it works together. It's also about trying to keep the integral part of the character and not taking the easy way out of trying to mimic human expressions and all that. You build from that but you try to keep it in character for WALL-E and EVE. WALL-E is a robot who's been on the planet for a long time and he's rusty and all that. EVE is this new machine. You have to be true to those characters in the animation.

The design sensibilities are that everything about WALL-E is on the outside and he's kind-of like this old bulldozer or something. He has this kind-of steel with yellow enamel paint that's been chipped away. There's a very relatable, tactile, construction machinery sense about him. EVE, by contrast, has all of her moving parts on the inside, and you see indications of that in the shoulders and the armpits. When you see the arm unfold you get a glimpse of the mechanism, of how she works, and that gives relatability to her. She could easily look too computery-soft. We tried to make that aspect work.

WALL-E was doubly interesting because it was probably closest to a bridge between live action film and animated film that Pixar has ever attempted. Live action footage has been integrated into the film and that had ripple effects throughout the production. Those choices created a texture for the world that had to be much more anchored in reality because when the live action came it in had to make sense with world. Hopefully that stuff works OK and doesn't feel too jarring. But it was definitely exciting to involve in that.

One thing that was exciting for me and was a nice fit for me was that Andrew had such a photographic idea in mind for approaching this. He wanted to, as he put it, get out of Andy's back yard and bring a photographic convention so that it had a feeling it was filmed rather than recorded on a computer. That was a nice connectivity for me since I'd obviously spent a lot of time trying to fit computer graphics into live action movies. It was nice to be able to be involved in that.