Building A Cheap Motion Capture Studio

 

By Ivan Hawkes
July 16, 2013

 

A while back I became interested in motion capture as a means to easily get basic animations into the game I am working on. Using reasonably priced software from Brekel and a cheap Microsoft Xbox Kinect camera you have the beginnings of a motion capture setup.

I’ve run a few experiments and the results are pretty decent for forward facing animations in a small area and at low speeds.

It’s cheap, easy to setup and effective enough for simple indie game development - and it can be improved upon without breaking most budgets.

Following some links on the net I stumbled on iPi Soft, an alternative to Brekel that is able to do a few extra tricks that can push your animation into the next level.

The iPi software is more flexible than Brekel and gives you the ability to ramp up the number of cameras and devices you use for capture. This can in turn lead to smoother animation, higher framerates, and greater accuracy even when the subject is doing a full 360 degree turn.

iPi allows you to use either two Kinect cameras or anywhere up to six Playstation Eye cameras (or other web cameras) along with Wii controllers and PS Motion controllers. A setup involving six PS Eye cameras and two or three PS Move controllers will give very good results for capture, hand positioning and optionally head tilt by taping one controller to the actor’s head. In addition, it allows for a much larger capture space, upwards of 6M x 6M, giving the actors room to move, fight or perhaps even dance.

There’s still a reasonable amount of cost attached to getting all of this, but it might be much lower than you imagine - especially if you are buying right now. Since the announcement of the new consoles for Xbox One and PS3 the price on all the gear for the old consoles has plummeted. Now is a good time to be buying it, even better if you don’t mind the gear being second hand.

Yesterday I was able to buy two XBox Kinect cameras for $30 each - they were $150 retain not so many months back. Worse, the developer edition, which you might want for close up work, sells for $300 retail and that price is not likely to drop. Then again, wait until the new year and they will no doubt have the new model out with better features at pretty much the same price.

I picked up six PS Eye cameras at the same time for a laughably low price of $5 each. They all work fine, so that’s a massive saving over the cost of them new a few months back - for $60 each. That’s six cameras for just $30, and as a bonus they make a great webcam for general use when can capturing motion video.

Slightly more expensive were the two PS Motion controllers I bought. These are currently $60 retail but I was able to buy both for $28 each second hand. One has a crappy battery, but even adding $12 to get new batteries for each sent from China - they still came out an OK price.

I still have a few more items I need to purchase:

  • 6 x mini tripods - $12 each
  • 6-8 x USB Extension Cables - $16 each
  • 8 x mounting plates for the cameras / Kinect - $12 each

Those items will allow me to place the cameras on tripods, secured with mounting plates, and run the oodles of USB cable needed to make them reach my PC. My PC has plenty of USB ports, which is a bit of an issue since you can only place one Kinect or two PS Eye cameras onto each port controller. This might bite laptop users, but it less of an issue if you have an up-to-date PC like mine.

Finally, you will need either onboard Bluetooth or an external adaptor if you wish to use the PS Motion controllers. This will set you back $10 or so.

That’s an entire motion capture studio you could put together for under $500, depending on how lucky you get hunting around for the gear.

The last thing you might need is a few lights to help brighten the scene to make capture easier. I have some really cheap paper lamps from Ikea which set me back $13 each. They are about 1.2M tall and put out a modest amount of warm diffuse light. Stick them on a box behind the tripods and they should give plenty of fill-in light if you need it. The PS Eye cameras are great for low light situations. Light temperate is not an issue, since this is motion capture, no-one but the animators is going to see the original lighting.

Now I have most of the gear and a few ideas kicking around I’m hoping to get some friends together and hire a local hall nearby. Beer, sandwiches and an afternoon of motion capturing fun - sounds good.