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Hello,

We developped a code that permits to send informations from Arena to our graphical renderer, we were inspired by the simple client code that we could get on the optitrack web site.

We have some questions about that...

1) Well, we wonder what kind of information can we get from the data->RigidBodies.Markers[][]? For the moment, we have the x,y and z position but we are interested in the rotation of each marker?

2) We tried to use other modules than rigid bodies (because we also wanted to be able to obtain only some specific markers and not the whole body's) but we weren't able to obtain any data from the other modules. How's that possible ?
Could you tell us if we can obtain the rotations of the markers that we are interested in with something else than rigidbodies ? is there any documentation for that ?


3) We saw that qx, qy and qz were the orientation of the whole rigid body, we wonder also what this orientation is ?

thank you in advance,
Sarah FDILI ALAOUI

What version of Arena are you using?

The version of arena we are using :
1.6.1000

Thank you
sarah FDILI ALAOUI

We didn't get any answer for this question, can you please give us a feedback on this issue ?

Sarah Fdili Alaoui

Hey Sarah,

1) Well, we wonder what kind of information can we get from the data->RigidBodies.Markers[][]? For the moment, we have the x,y and z position but we are interested in the rotation of each marker?

Markers only have positional information, not rotational. RigidBodies created from markers contain position and rotation.

2) We tried to use other modules than rigid bodies (because we also wanted to be able to obtain only some specific markers and not the whole body's) but we weren't able to obtain any data from the other modules. How's that possible ?
Could you tell us if we can obtain the rotations of the markers that we are interested in with something else than rigidbodies ? is there any documentation for that ?

In short there are 3 types of data streamed by NatNet:
1. Marker Data
2. RigidBOdy data
3. Skeleton Data

Refer to the NatNet User's Guide for more info.

What is actaully streamed depends upon what you have defined in Arena and/or TrackingTools and what streaming options you've selected From the Arena/Tools streaming panel.

Note that markers, intrinsicly, do not have orientation, just position.

3) We saw that qx, qy and qz were the orientation of the whole rigid body, we wonder also what this orientation is ?

Quaternion. SampleClient 3D has example routines for converting from quaternions to eulers. See the NatNet User's Guide for more information.

Hope this helps.