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1.- Does a larger spheres improve tracking always? in a small room i have seen that with a larger spheres i get worse results.

2.- I want to get a more reliable tracking when doing high speed turns. Is there a way (aiming the cameras in some way, changing sphere positions, putting more spheres...) to obtain a tracking with no lose of position when moving fast?(or with very few loses)

3.- As one of the objects will represent a camera, i need the less noise i can from the rigid body tracking so, playing with exposure, threshold or intensity could i get better accuracy? if that's so, what would you recommend?

The room i�m using is small (5x5 meters aprox).

Thanks in advance.

1 - Larger sheres allow for greater distances that can be tracked from the camera.

2 - Getting better tracking tends to come down to the number of cameras that you are using, and the quality of the calibration.

3 - The intensity settings should not be adjusted at all, as a general rule. As far as noise goes, this can be caused by other IR points being picked up by the software, or the calibration being slightly inaccurate.

After some research, we have got a good calibration only a few times.
The tracking tools software always reported calibration accuracy as excellent but, as i have said, only few times was good.

The question is, How do we know the calibration is correct? Is there a method to calibrate properly?

There are several training videos posted on wanding technique -

http://www.naturalpoint.com/optitrack/p ... ideos.html

There are a number of factors that can adversely affect your ability to achieve the best calibration results.

1. Aim all cameras to a single central location. The cameras could be in an arc, circle, or rectangular arrangement. Confirm by reviewing 2D camera previews that all cameras are approximately aimed on a single point.

2. Review 2D camera previews and verify there are no unwanted markers. If you have unwanted markers, remove them from the camera's view, adjust the camera exposure and threshold settings, or block visible markers to remove unwanted static markers.

3. Remove any reflective material on your person. This could include jewelry, reflective emblems on clothing, belt buckles, etc. These can cause false markers that are injected into the calculation and cause the camera calibration to fail.

4. When wanding, wand the entire volume and ensure by reviewing the 2D camera previews that you've achieved proper coverage on all cameras.

5. If your camera calibration still fails, optionally increase the Minimum Camera Coverage calibration parameter to match the number of connected cameras. This will force all wanding samples to include data from each camera.

6. If camera calibration problems persist, email support@naturalpoint.com for additional instruction.

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All this information aside, we are planning on releasing a new version of both the Tracking Tools and Arena in the very near future that should be easier to achieve more accurate calibration results and will likely resolve your issues as well.