Streaming markers data of a rigidbody

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danagn
Posts: 5
Joined: Thu Oct 12, 2017 4:51 am

Streaming markers data of a rigidbody

Post by danagn » Tue Apr 03, 2018 10:14 am

Hi all,

I'm trying to track at real time using motive and NatNet packetclient an object with 5 markers, 4 passive and 1 custom LED which is activated by pressing a button.
I tried to create a rigidbody with all the 5 markers. Normally I would expect the rigidbody to be tracked with the 4 markers and when the LED is active with all the 5 markers, but this doesn't happen.

I tried also to create two rigidbodies, one with the 4 passive markers and one with all the 5 markers.Again I would expect, when the LED is inactive the rigidbody 1(4 markers) to be detected and when LED is active, rigidbody 2(5 markers) to be detected. But again I didn't managed to this.

Please could you help me with this and how I should do it?

I hope I explained the case well enough...

Thank you in advance.

steven.andrews
NaturalPoint Employee
NaturalPoint Employee
Posts: 455
Joined: Mon Jan 19, 2015 11:52 am

Re: Streaming markers data of a rigidbody

Post by steven.andrews » Tue Apr 03, 2018 11:38 am

Hi danagn,

If one rigid body is already tracking on 4 out of 5 markers intended for use with another rigid body, this could prevent the second rigid body from tracking. Results may be different if you enable the Share Markers setting in the rigid body properties.

Instead of trying to track two rigid bodies on top of each other, you may want to use the one rigid body defined with all of the markers, including the LED. Through NatNet, you can check the status of the individual markers to determine if they are being tracked. The rigid body will show as tracking the entire time, but the individual marker will report as untracked when the LED is off and tracked when the LED is on and recognized as being part of the rigid body.

Best,
Steven
--
Steven Andrews
OptiTrack | Senior Customer Support Engineer
help.naturalpoint.com
support@optitrack.com

danagn
Posts: 5
Joined: Thu Oct 12, 2017 4:51 am

Re: Streaming markers data of a rigidbody

Post by danagn » Wed Apr 04, 2018 3:42 am

Hi Steven,

Thank you for your reply.

I managed to get the correct indications using the labelled markers and the modelID.

However, checking the flags bOccluded, bPCSolved, bModelSolved, packet client returns the same for any kind of marker (passive/LED) or extraneous reflection showing false, true, false for the respective indicators. So everything is pcsolved as I understand, isn't it?

How could I fix this?

Thank you again for your time and help.

steven.andrews
NaturalPoint Employee
NaturalPoint Employee
Posts: 455
Joined: Mon Jan 19, 2015 11:52 am

Re: Streaming markers data of a rigidbody

Post by steven.andrews » Wed Apr 04, 2018 3:57 pm

Hi danagn,

After checking with our engineers, it appears there is a bug currently causing some of these flags to be reported incorrectly.
Unfortunately, it sounds like it may be a while before we are able to fix this one.

There is somewhat of a workaround that could work for the time being. You can go through the Rigid Body markers list to determine where markers are expected to be. You can then compare this against the raw list of markers to determine if one of the Rigid Body marker is not there. This is a bit clunkier than we'd like, but it would allow you to determine if your marker is on or off. It should also work better than trying to track two rigid bodies on top of each other.

Cheers,
Steven
--
Steven Andrews
OptiTrack | Senior Customer Support Engineer
help.naturalpoint.com
support@optitrack.com

danagn
Posts: 5
Joined: Thu Oct 12, 2017 4:51 am

Re: Streaming markers data of a rigidbody

Post by danagn » Thu Apr 05, 2018 6:08 am

Hi Steven,

Thank you again for you response.

I finally made it with one rigidbody and checking when 4 or 5 markers are tracked.
It works for now and hope it'll keep working this way!

Many thanks again, Cheers.

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