nofarb17 wrote:
I'm not sure quite how to handle a much larger capture area (more rectangles? more spirals?). I think it might be an issue with cameras in the round instead of just being on one side of the actor.
I would just make a bigger table shape, maybe with more legs, and a broader spiral or some random pattern inside. Keep is simple but cover a large enough area to make up for the greater distance between camera. Making a complex pattern won't neccessarily improve accuracy; more likely it will just cause DMC to take a lot more time to solve the calibration.
As for camera arrangement, if you only have four cameras, I recommend a semi-circle like the one I use. The relative closeness of the cameras helps DMC understand the relationship between the images. With six cameras you can widen the circle for greater coverage or keep them within a semi-circle for greater precision within that semi-circle. The advantage of a full circle is that there is less chance of self-occlusion and the advantage of a semi-circle is that you get data that is more focused and accurate when performing 'to the camera'. The formation you choose should depend on the type of action you want to capture. The size of your capture space may also help you decide; I chose a semi-circle formation because of my relatively small shoot space (a two-car garage.) With a semi-circle, I can get about 6 to 7 feet of useable performance area, which is good for many actions including short walks, jumps, martial arts and tumbles. I might even be able to get a small run cycle if I plan on looping the action in Animeeple or Motion Builder (not ideal but doable.) But if I used a full circle in my current shoot space, the performance area would be much, much smaller--too small to bother with in my opinion. If I had to shoot in a very small space (like a living room or single car garage,) I would seriously look to the Kinect Sensor for capture.
As a matter of fact, we ordered a Kinect this weekend specifically to use at home. We figure this would give us a quicker way to capture simpler actions without leaving the house. (We will still to transport our 'mocap computer' to our off-site stage for more complicated motions.)
Quote:
...but the issue with DMS not working well with camera roll might be an issue there too.
Roll really should not be an issue because the PS3 Eye cameras themselves do not physically roll, and I believe the software expects the cameras to be set up in a fairly straightforward manner (height and tilt only.) My suggestion is to keep your camera setup simple; just mount the cameras on vertical stands (tripods or c-stands) for height and use the camera's base for tilt to look up or down;
do not 'dutch' the cameras. If you're positioning the cameras in unusual angles this may just confuse DMC because it may not be what's expected by the software or what the developers intended.
BTW, I modified the base of my PS3 Eye cameras using a Helicoil kit so that they can be mounted like a regular camera. I'll post a video for how this is done; the mod is easy to do and I highly recommend it for improved stability. Alternatively, in the past I've used plastic clamps and velcro to 'lock down' the cameras; not as stable as screw mounts but okay for short term setups.
Hope this info helps. Remember, keep things simple; don't make DMC work harder than it needs to and you'll get the superior results.
G.
