In making an animated movie heaps of money goes in all sorts of places besides the animation itself. Writers, directors, actors and all the other production cre

In making an animated movie heaps of money goes in all sorts of places besides the animation itself. Writers, directors, actors and all the other production crew folks etc... distribution, advertising and so on... Who knows what the break down is - and whether the choice to use source is based on cost efficiencies alone. Perhaps they are going for a particular visual style... I would have thought the source engine is sufficiently old enough to give such a film an interesting retro aesthetic...