Camera tracking with Moujou
June 27, 2006 1:43 am
Besides animation, one of my biggest interests is filmmaking. Being so passionate about the computer animation field, I am always looking for new things to do and new techniques to explore. These last months I grew very keen to make a movie that would combine live action footage and computer generated elements. Actually, this can be considered an "every-day thing" for visual effects studios, but for me it's a realm that I have not explored yet.
To help you combine digital and real elements, it's often recommended to use Camera Tracking software. There are different software packages that will help you do camera tracking, such as Matchmover by Realviz and Boujou by 2d3. 2d3 has recently released a plugin for Maya called Moujou, that is supposed to yield the same results as Boujou directly from within the Maya interface. I took Moujou for a test drive and I found it to be an intuitive and simple tool that does the job that it's supposed to do.
When I said that Moujou was a very simple tool, I meant exactly that. You open up the Moujou window, then you select the sequence you want to track, change a couple of camera parameters, and then you just click on the "Track It" button. Soon after you do this, Moujou checks your image sequence and does the tracking. When it's done, it will create a camera that shows the final result. You are also given a certain number of locators so you actually know where everything is.
Moujou is based on the same camera tracking algorithm as Boujou 3, so if you know Boujou you know that you can expect very nice speeds. This also means that, in theory, you will get the same results in Moujou as if you were using Boujou 3. On the other hand, 2d3 states that sometimes you may need some additional tools that are not included in Moujou, so you may find yourself in the need to use either Boujou 3 or Boujou Bullet. Nevertheless, since I am not familiar with any of those, I can't say whether or not this may actually be the case.
I found that image quality plays a very important part for Moujou, not only on the result, but also on the speed. The lower the quality, the longer it takes Moujou to track your camera, and the results are not going to be that good either. Another thing to keep in mind is the camera type that you use, because that seems to affect how your virtual camera behaves in Maya. Moujou supposedly includes some "camera presets" so you can choose the camera type from the list, however the demo version didn't seem to include those, so all I could do was guess.
Since I don't have a nice camera of my own, I had to borrow one to run the tests. The downside is that I had to return it so I couldn't work with my own footage as much as I wanted, so I used footage from movies to test Moujou. Sometimes the result would be simply perfect, but sometimes I would get some parts where the tracking was not so good, or the camera would jitter a little. I noticed that elements such as heavy motion blur and defocus would greatly affect the camera tracking as well. When I used a clip of a movie for testing purposes, it took Moujou a while to actually reach a perfect tracking, being the part with heavy distance blur and motion blur the one that didn't track so well.
By using that movie clip I also meant to check how Moujou would bejave with moving objects. The clip not only includes moving objects, but also a very large crowd of soldiers running around. Just as I was expecting, Moujou could tell the moving objects from the background so the virtual camera would follow the real camera, not the soldiers.
I had never worked with the guys at 2d3 before, so I didn't know what to expect from the technical support department. But after running into the first problems, I found tech support to be really efficient. I would get my answers in less than one day.
With a pricetag under $800.00, Moujou can be considered a great option for people that want to start with camera tracking. It's a simple and yet effective tool that will give you decent results if you take into consideration the video quality issues that I mentioned. If you are interested in camera tracking, I encourage you to download the demo version available at the 2d3 website so you can see for yourself.
Check out the following video samples (in WMV format):
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