Using projection mapping to film the world's tiniest police chase

The Theory explain how they created their innovative short film involving cops, cars and pico-projectors.

"We took the helicopter footage and used AE’s built-in Tracker to track each of the four points as the helicopter flew, and Perspective Corner Pinning to track the four marker points."

In this Masterclass, writer/director team Tom Jenkins and Simon Sharp, otherwise known as The Theory, reveal how they created their award-winning short film Speed of Light

The duo believe self-initiated work is very important when it comes to developing skills and technical concepts that would be too risky for a paid-for project. Speed of Light was created after they had the idea of a developing a traditional projection mapping concept on a micro scale, using Pico projectors that could be easily moved around.

The team came up with the concept of a classic car chase. They filmed against greenscreen backgrounds, then enhanced this in After Effects, before projecting the isolated images and filming the results.

Time to complete 

9 months (between other paying jobs)


Avid Media Composer 5, After Effects 5.5, Red Giant Trapcode Particular, Canon EOS 5D Mk II, iPod touch

Testing is always the first part of our process, and often the most important. For Speed of Light, we tested to see whether the concept of projecting small isolated images (with a pure black background) onto various surfaces actually worked and looked good. Luckily, we found it did.

Music is a big inspiration, so we try to source it before we begin thinking of visual or story ideas. For Speed of Light, we found a great piece of production music which, although needing a bit of editing, had the right tone and feel for what we wanted to do.

I don’t know if we made up the word ‘Scriptmatic’, but it’s an Animatic storyboard with text instead of visuals. In Avid Media Composer, we edited a bunch of text descriptions of shots to the music, so as to get a feel of the sequence without having to spend time storyboarding. It’s a really quick way to play around with ideas.

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Next, we needed to film the raw elements that would be projected. We filmed everything against a greenscreen, so we could key out the backgrounds later. 

We hired a greenscreen treadmill to film all the running shots on, and drove the model cars on it as well to give a realistic feel to the moves. 

We filmed a small model helicopter against a greenscreen, too. We wanted realistic spinning rotor blades, and the simplest way to do these is to create them as simple VFX in After Effects. We added four push pins as very rough visual markers of where the blades would be. We’d track these later in AE, and build the whirling blades from the tracked data.

We now had the greenscreen rushes, so we took them into Avid, replacing the scriptmatic descriptions with the actual shots. This gave us a rough sequence of the best raw shots, which we individually exported to After Effects. 

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Next, we used the Keylight keyer in After Effects to remove the greenscreen backgrounds. Rough garbage mattes were used on some shots where the greenscreen wasn’t lit perfectly, or where the edge of the actual greenscreen could be seen. We also added some extra skidding moves to the cars where needed.

The next task was to add the rotor blades to the helicopter. For this we created a simple square composition, with a white bar shape rotating quickly, like a rotor, then turned on motion blur.

We took the helicopter footage and used AE’s built-in Tracker to track each of the four points as the helicopter, and Perspective Corner Pinning to track the four marker points. Next, we applied the data to the rotor comp. With a bit of tweaking this worked really well. 

For the trail on the heat-seeking missile, we used Red Giant’s Trapcode Particular plugin. We took one of the presets and tweaked it until it looked right, then we added an image of a missile to the front of the trail and comped it together with the helicopter footage. It’s our favourite shot.

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After rendering and importing the shots back into Avid, we recut the sequence using the comped shots to see how it looked. We refined the shots and edits, and reshot a few bits. When finished, we were ready to put all the shots onto an iPod touch, plug in the MicroVision pico projector and start capturing the actual film. 

Although it appears that the camera and projector are handheld, we built a number of wheeled rigs to hold them accurately in alignment. This was essential for making sure the projected images always appeared at the correct angle on the camera.

We had to distort them, so when they were filmed at a certain angle the distortion would be cancelled out. This is the same principal as the adverts painted on football pitches, and is called anamorphic perspective.

Now it was time to film everything. On our little wheeled rigs, we clamped a tiny full HD camera with a massive wide-angle lens to give us a very large depth of field. This had the effect of making everything feel huge, and made any camera movement feel much more dramatic. 

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With the bulk of the filming complete, we went back to Avid to recut the sequence again, this time adding the final rushes. The key to this part was refining what we had, rather than trying to do anything new.

We chopped the sequence from a baggy three-and-a-half minutes to a much snappier two. It was essential to even cut out shots that we loved to quicken the flow of the piece, and keep it fun and exciting.

When we were happy with how the sequence flowed, we took everything back into After Effects for polishing. We added subtle camera shake to give it a handheld feel. Specific parts of some shots were graded by adding Adjustment Layers above them, then animating simple masks to restrict their impact.

We went back to Media Composer to give it a final overall grade, sound design and mix. It took a long time to source and edit the sounds for Speed of Light, but we needed a rich, deep soundscape to help ‘sell‘ the high octane chase – so the effort was worth it. 

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Finally, we added a short title and credit sequence. We’ve noticed that on some short films these are as long as the actual film, but we think it’s a good idea to keep them short, sweet and of a similar tone to the rest of the film.

Tom Jenkins is half of production company The Theory. It’s the pseudonym for British writer/director team Tom Jenkins and Simon Sharp. Their goal is to find bold, beautiful and unique ways to tell stories. 

Since forming, The Theory have had a major impact, picking up a host of awards and a legion of fans along the way – most notably for their viral smash hit short Address is Approximate. The film scooped the Jury award for Best Animation at the 2012 Webby’s, and boasts Google’s Larry Page and actor Kevin Spacey among its many admirers.