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Hello!

We bought an Optitrack 6 camera system with Arena. In the last few days and weeks we've tried to optimize our setup of the tripods and cameras as shown on "mocap-camerasetup6.jpg" on the Optitrack webpage. The diameter of our camera circle is about 6,10m (=20') and the height of the cameras is about 2,00m (=6,56').

Now I've looked at the demo video "fluidImages_Demo2.mov" and saw at 00:59min that the 6 camera system which is used in this video has different camera heights at each tripod. On "mocap-camerasetup6.jpg" you can see that in a 6 camera system the camera height should be constant so why are the tripods in the video installed differently heigh? Is there a possibility to get better results with different camera heights?

Greetings SSK

Hello:

For a 6 camera camera circle setup, I would recommend a smaller overall diameter, more like 15'. The picture says 10'-20', 20' being the maximum. I would also put the cameras higher up, 8' is perfect.

You want all the cameras pointing to the same spot in the center of the volume, about chest height. I would probably also rotate all the cameras to be 90 degrees, on their side.

Are you getting good captures? Can you calibrate with this setup?

We usually recommend a conservative camera placment / setup to begin with, then when you get it calibrated and become more comfortable with the setup, you can change the camera positions to get better coverage.

Also, we have just released a new version of ARENA (1.2), that has a much improved calibration engine. It should be easier to get a good calibration now, as long as the cameras have good overlap and are pointing to the center of the capture volume.

Hello,

thanks for your fast answer. The next time we will try your given values (15' diameter and 8' camera height).

Do you mean that we should not put the tripods + cameras in a circle but rather in 2 sides each with 3 cameras?

The calibration with our present setup is very different. With fast calibration the results of the 6 cameras range from "great" to "excellent". But the longer the calibration takes the worse are the results e.g. with slow calibration the results of the 6 cameras range from "poor" to "good".
The captures are only in the middle of the capture volume good. Otherwise the model has a lot of red an yellow body parts.

The ARENA Version 1.2.034 is a public Beta. Is it really advisible to use this file in this state yet?

With the best regards
SSK

Hello:

I would keep the circle layout for 6 cameras, it works the best.

I would not hesitate to try the new 1.2 Beta, we have tested it a lot and it is stable. It will give you much more reliable calibration results and that sounds like it could help.

Thank you for all the details you have given. I will advise you of our calibration and capture results with the new settings and the new Arena version.

Regards SSK