[IGSTK-Users] spatial object after expired data validity AND tracker updating signal instead of position

[Andinet Enquobahrie]

> Hi Andinet,
>
> Thanks for the answers. I will do that. I have two other questions though.
>
> What happens if I attach a view to a tracking tool and the 
> communication gets cut off in between? Does the entire view window go 
> blank?

After the communication is cut off, then the transform time stamp will
expire at some point. When it expires,  the tool representation should 
disappear.
This is only true for spatial objects with finite expiration transform time.
Image spatial objects are assigned by default the maximum allowable
expiration time and hence  even if the communication is cut off, they will
be still visible.

Let us know if you are not observing a similar behavior.

>
> Now I am attaching my spatial object to a tracker tool and tracker 
> tool to a tracker. The tracker's parent is a world reference. So, a 
> position of (0,0,0) on the tracker implies the world_reference. Is 
> that correct?
Yes, that is correct.

If the tracker is the "world reference" ( in other words if your  
tracker and
world reference coordinate system have identical transform relationship) 
then
the tracker tool measurements reported by the tracker are indirectly with
respect to your world coordinate system.

-Andinet
>
>
>         Hi everyone,
>
>         I have noticed that in case I lose connection to my tracker,
>         the spatial object connected to it disappears after the data
>         validity time has expired. Would it be possible to change the
>         color of the spatial object, say from green to red, rather
>         than letting it disappear altogether?
>
>     You are correct. The current behavior is that the object will
>     disappear if the transform
>     time expires. We would like to keep it as it is in cvs ( main
>     distribution )
>     However, for your own use, you can locally modify the state
>     machine configuration in
>     ObjectRepresentation class to be able to change the actor color
>     when the transform
>     time expires.  It is straight forward to do that.
>
>     In the
>     ObjectRepresentation::RequestVerifyTimeStampAndUpdateVisibility()
>     method,
>
>     1) InvalidTimeStamp input gets invoked if the time expires,
>     otherwise the ValidTimeStamp input
>     will be invoked.
>
>     2) These state input will initiate a transition to methods that
>     will turn on/off the actor
>     visibility. All you need to do is modify these methods and change
>     the actor colors instead of
>     turning on/off the visibility.
>
>
>         Also, I need to write a tracker for spirometer input through
>         NiDAQ. Now, by default, a tracker updates a transform. But
>         mine's more of a signal (breathing) than position. Should I
>         just write it that the signal is one axis of the transform
>         with the other two set to zero? Is there a better way?
>
>     Yes, for minimal change, you can store the signal value as one of
>     the components
>     of the translation vector of the tool transform and keep the
>     others to zero.  You will need
>     to write NiDAQ specific tracker and trackerTool classes. You might
>     want to start
>     with the current tracker classes.
>
>     Let us know if you more questions..
>
>     -Andinet
>
>
>
>
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>
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>
>
>
>     -- 
>     ==========================================================
>     Andinet A. Enquobahrie, PhD
>     R&D Engineer
>     Kitware Inc.
>
>     28 Corporate Drive
>     Clifton Park, NY 12065-8662
>     Phone: 518-371-3971 x124
>     www.kitware.com <http://www.kitware.com>
>
>
>


-- 
==========================================================
Andinet A. Enquobahrie, PhD
R&D Engineer
Kitware Inc.

28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x124
www.kitware.com