We asked the team about the evolution of the Tiny Worlds trilogy of short films – see the series in Related Content:

A key creative decision we made early on, was how to approach the various effects (smoke, water splashes, explosions, etc.) when dealing with a world being shown at such a small scale. We quickly realised that if we had decided to create the effects in a photo-realistic manner, then things like the torpedo impact would end up looking more like a Chinese-firecracker, rather than the dramatic explosion that we wanted to show.

At this point, we decided to use 2D hand animated elements to represent the effects instead. This had the immediate benefit of releasing us from the photo-real constraint and added a stylised feel to the piece, all without sacrificing the suspension of disbelief. After a few early tests creating the animated effects in Maya, it was obvious that this was going to work really well.

Any other challenges?
 
The other tricky challenge that had to be solved was how to get the submarine to interact with the live action footage of the puddle. After exploring a few possible solutions, we decided to build the puddle in 3D and carefully recreate the reflections, as seen in the original footage. A ripple simulation was generated in Houdini based on the submarine animation, and everything was carefully blended together in Nuke to make sure that we could keep the reflections of the people as they walked by.