I was responsible for the 3D models and animation of the planes and pick, and also for the smoke simulation (for the rotoscope stage).
The smoke was made with the standard Blender particle system, where the particles were displayed as a group of Icospheres to make the rotoscoping stage a bit easier. It was not the intention to achieve something photoreal here, but just a nice flow to make it easier to draw the smoke in 2D. The Blender output was like this:
Our goal was to achieve a somewhat flat look, so 3D couldn't look too "3D". To achieve that, I've used three separate RenderLayers: one for the flat colors of the plane (using only the "Color" pass); another for the sharp shadow, where I used a Sun lamp and used only the "Shadow" pass, mixed with the color; and a third one for the windows, to allow the creation of masks on the compositing stage. In the plane RenderLayer I've also applied some toon edges. I didn't use the standard Blender edge settings: instead, I've made a mix in the Node Editor with some filters, to achieve edges a bit more irregular.
The basic node setup for the plane takes was like this one below:
Now a plane turnaround, with the wireframe view:
Another thing was the mix between the hand made drawings and the 3D renders. Along with the flat look, we had to make them the same frame rate. The 2D animation was made on "twos" (one drawing is held for two frames), so the 3D animation was rendered likewise. To achieve this in Blender is very simple: I've made the animation normally at 24 frames per second, and just changed the "step" setting on the Anim buttons in Blender. This setting forces Blender to skip one frame when rendering:
For the tube scene I've made an Array of rings with a Curve modifier.
The plane on this scene was parented to the Camera, which had a Follow Path constraint to the same curve. For this scene I have also rendered a Z depth pass to be used in the composition stage, as you can see below:
The whole process was very laborious, but we're all very happy with the result. Here the complete list of credits: