Setting up a Motion Capture System – Twelve Camera Flex 13

Back in June funding was made available by the University for the purposes of capital asset acquisition. The School of Computing put in a number of bids for equipment ranging from Eye Tracking and Networking to Video Production and Motion Capture. Two years ago when a similar opportunity came around, I suggested the idea of acquiring a Motion Capture System.  It really boils down to a question of cost benefit analysis. At that particular time any reasonable system would have been very expensive, so we ended up purchasing a Render Farm instead as we had quite a few students doing work in 3DS Max and the extra horsepower to quickly render out thousands and thousands of frames of animation seemed like a far more useful resource to have. I spent quite a bit of time during the summer of that year looking over render farm specs along with our Computer Systems Manager, we eventually settled on a 64 Core system.  At that very same time as well, we also purchased a fairly high end 3CCD video camera, about 6500 watts of lighting for the Green Screen Room, and a few other bits and pieces.

With this year’s funding we finally decided to take the plunge and get a Motion Capture System. Quite a bit of work has been done in the past two years regarding 3D modelling and animation. So a motion capture system would greatly add to this, providing us with the ability to readily animate the 3D characters produced by our students.

The time frame for putting the documentation together for the funding bid was quite tight so it transpired that I ended up putting the material together for the Video Production and Motion Capture System whilst I was out-with the country on holidays. Towards the end of August the proposals were signed off and approved, so I spent a fair bit of time putting together a finalised shopping list that should provide the school with some really interesting equipment to work with. Throughout most of the month of September various suppliers were found and the various items put in for purchase, with the last item (a piece of equipment for camera stabilisation) being finally sorted out just a few days ago. Colin our Computer Systems Manager tracked down a company selling the Flex 13 Camera system. It came on the market around April 2012, and has some interesting specs such as 1280 x 1024 resolution running at 120fps. After quite a few emails it was finally decided to go with a 12 Camera system with a Medium & Large MoCap Suit.

On Wednesday 26th Sept the Motion Capture System finally arrived, so I spent the afternoon going through all the parts and checking all was ok. On Thursday evening Eyad (a fellow lecturer) and myself went about setting up the system in our Green Screen Room. We got all the stands setup, cameras mounted, and all the cabling in place. Then we set about installing all the necessary software on one of two new Z400 workstations that we had purchased just a few months previously. The software installation was quite straight forward, but we ran into a problem with the registration of the software license. The error was that it couldn’t find a network. It was around 21:00 in the evening so we decided to leave it for the day and get it sorted out when the Systems team were in the next day.

Friday morning I called in to see Colin and Tommy to see if the software license issue could be sorted out. We first of all began by transplanting the workstation from C5 into the Green Screen Room, it was then necessary to enable some of the network ports in the room so we could get the machine up and running on the computer network. All went well and within a short while we were able to try getting the license sorted out. So with the Motion Capture system now powered up and connected to the Workstation and network connectivity established we tried entering all the license details, but ended up getting the very same error as encountered by Eyad and myself the night before. We were finally able to register online through a web browser and received the license key via email.  Within minutes of saving the license key to disk, the Arena Motion Capture Application was fired up, and the video feed from all the cameras started streaming in. So with the full system now operational we left it at that for the time being.

Yesterday (Saturday) Eyad and myself spent the afternoon at Uni aligning up the cameras correctly, calibrating the system, donning the motion capture suit and carrying out the first test of the system. Calibration consisted of Wanding the area to establish the capture volume, followed by the establishment of the ground plane and then the final phase of Skeleton Calibration i.e. getting the system operational for a specific individual. At the time we left the building (just before closing), we had managed to capture a bit of movement, I tried out the standard Calibration T-Pose followed by some golf swings (even though I don’t play golf).

As of now, the system is working well, though it will be necessary to go through the final Skeleton Calibration for myself, before it is finally configured correctly to accept motion data generated by my movements. It will be great to complete this final stage and see what the system can really do. All in all Eyad and myself have spent in excess of 20 man-hours (excluding the time spent going through documentation / tutorials) getting the system to its current operational state. Overall it was quite simple and straightforward to setup, just needing some time and patience. A large portion of the video production / graphics equipment on order is still in the process of being delivered, so hopefully it will all be in place within the next week or so. Sounds like an exciting semester ahead between now and Christmas.

The following videos above and below should provide an overview of some of the steps involved in the process. Quite a few more can be accessed from the following playlist showing most of the steps involved. Enjoy.

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4 thoughts on “Setting up a Motion Capture System – Twelve Camera Flex 13

  1. How are you liking your OptiTrack Flex 13 system? I’m looking at the same or possibly splurging for a Vicon system, but the price point for the Flex is much more within reach. I’m interested in how it handles missing markers, like for example when an actor is laying on the ground, or doing a push up, or a sit up. Have you tried any of these scenarios. Any tips or other things you’ve learned along the way that would have changed your decision?
    I also noticed that you have a pretty small room in the videos above, how has that worked for you. What is that room size and then the effective capture area?

    • Have moved it to a slightly larger room & immediately found setup e.g. calibration of T-Pose was much easier. Will be moving to another room roughly 7meters square and will be fixing pipe along the walls at a height of about 8 feet, therefore instead of having 6 stands at present with cameras mounted at 6ft and 8ft, all 12 cameras mounted at 8ft will give a far greater spread of vision, therefore should more readily pick up the markers. A room 20 to 24 feet square is ideal. The capture area would perhaps be 2 to 3 feet in from the cameras. So a room 20 ft square may give you around 14 -15 ft of an capture area.

      Had to watch the videos at (http://www.youtube.com/user/NaturalPointInc) to figure out how to set the system up and get it configured.

      A pushup of similar would cause issues in detecting markers, really do need to see it operating in a larger room to really get a sense of its capabilities.

      http://www.naturalpoint.com/optitrack/products/flex-13/indepth.html

    • For a system as you have seen here you would be looking at around the £15K to 20K mark. Going for a higher resolution system capable of a much larger area then it can easily move into the hundreds of thousands.

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