Visual Effects: Will MacNeil
Matchmove Artists: Will MacNeil
Production: Liberty spot "Where Do They Go"

It's unusual to undertake a project for an organisation without their knowledge in the mere hope that they might like it and subsequently commission it, but for talented, award winning motion graphics artist and television editor Will MacNeil this strategy is almost becoming a habit. A new spot for the human rights organisation Liberty is a cleverly conceived idea that features some complex tracking and compositing work and was shot, edited, tracked and animated by MacNeil himself.

The spot seeks to draw attention to the UK Government's deeply unpopular plans to create a central database to hold citizens' private details and its appalling record of keeping such data private. Central to the concept was the use of The Pixel Farm's comprehensive tracking kit, PFTrack. The point is made by showing documents freely leaving official buildings, flying out of open windows and converging in the shape of a person who in turn is shown freely leaving such buildings to casually wander around the world at large unhindered. All the 3D work was done in Maxon's Cinema 4D, the compositing in Apple Shake, while every shot was tracked in PFTrack.

What makes the project a little unconventional is that it was made entirely by Will MacNeil and without the knowledge of Liberty itself. "I came up with the concept, produced the ad myself and then presented it to Liberty. As I had hoped, Liberty liked the ad." Explains MacNeil, adding, "I suppose it shows my confidence in PFTrack in that I knew I could produce the shots at virtually no cost."

Indeed this is not the first time that MacNeil has adopted this strategy. He produced a similar type of project last year for Amnesty International. "I used PFTrack to matchmove shots where people were signing their name in the air. I built a 3D stroke effect around the signature which looked good. But what gave the effect strength was the matchmoving. When the signature hangs in space and the camera moves around it, it becomes more than just an effect, it becomes part of the scene. I think it feels magical." For an effect that appears quite simple it actually involved a good deal of complicated tracking work for which PFTrack proved itself the ideal tool. Each shot had to be tracked twice. First as a 3D matchmove that created a scene with a keyframed camera for use in a 3D application, and then as a 2D track following the actors hand. The results were flawlessly good and after a short spell on YouTube, Amnesty contacted Will to commission the idea for a TV advertisement.

Several of the shots in the Liberty spot also presented a number of problems, though PFTrack's broad range of versatile functions helped solve these quickly and accurately. Its intelligent tracking algorithms and object tracking capabilities allow for independent motion within a shot to be tracked along with the camera motion, and then each motion group can be exported separately or together. Both useful and a great timesaver, this functionality proved helpful for the final shot which used more than one motion group, tracking the camera's movement and the boat's.

Additionally PFTrack allows you to create mattes to obscure distracting motion from the principle camera solve, though this is not always necessary as Will happily discovered. "Early on I was worried that I'd have to deal with lots of conflicting motion in the frame. Things like cars and people moving about can confuse the tracker and give you bad solves. So to start with I used a lot of mattes to block out motion. But as I progressed I realised this wasn't necessary. PFTrack is smart enough to see the principal motion and ignore the others. This is a huge timesaver."

Another unique function of PFTrack is Extended Tracking which allows you to save tracking data even if a solve fails. Sometimes a solve may fail due to just a few frames of incongruent motion. PFTrack allows for frames to be added to combat this and so extend the tracking data avoiding the need to start from scratch. MacNeil comments, "I use extended tracking quite a bit, especially when I got conflicting motion in the shot. If I solve the clean' portion of the shot, I can extend this without worrying about how other movement in the frame might throw off the solve." He goes on to mention another helpful and timesaving function, "I also use the camera f-curves to repair frames now and then. My camera for this was not high-end. Occasionally I'd get strange compression artifacts that might throw off the trackers. It was a help to be able to dig into the camera curves after the solve and see if anything had been thrown off, and then of course repair this." These repairs can be made directly from a graph editor in the timeline. Corrections are quickly added to the camera solve without needing to re-solve each parameter in the sequence.

Version 5 of PFTrack also includes a Focal Length Estimation tool that provides an easy to use graphic means to calculate focal length. This can make an important difference in obtaining an accurate solve and is so helpful for those numerous occasions when such camera data is unavailable. Will MacNeil was certainly grateful for this integrated tool on this shoot as he explains. "I was shooting on the run around Central London. I was looking for buses, boats, anything that might work in the ad and I didn't always have time to check my focal length. I just wanted to frame it and shoot it. So I got to the tracking stage with almost no idea where I was on my lens. Using the estimate focal length feature I could quickly get basic lens information and have a workable ground plane. Even on shots where I didn't need a 3D camera solve, I still used this feature to help set things up."

One particular feature of PFTrack that has won a legion of admirers is its Geometry tracking capabilities, where geometry can be imported into the application and using range of provided tools precisely match that geometry to a desired element of the plate. A unique element of the application MacNeil is currently utilising with relish. "I'm working at the moment on an ad about bullying. I'm using a feature I've always wanted to exploit Geometry Tracking. The effect calls for some serious digital facial prosthetics. I can't think of a better tool for this than PFTrack." And in summing up his feelings about using this particular tracking tool over lesser rivals he comments, "I choose my software carefully. I don't just look at what people have made with it, but at the community of users and the company behind it. There's always been a vibe about Pixel Farm products that feels exciting. I often go to the website just to see what new tools they might be adding. I like the way the Pixel Farm keeps adding features and opening up new possibilities." When asked to comment on MacNeil's remarks, The Pixel Farm said that they couldn't possibly disagree with such a genius motion graphics artist as Will MacNeil.

For more information, visit: www.willmacneil.com

Words: Martin Southwood