[IGSTK-Users] Multiple tracking systems

[alberto.vaccarella at mail.polimi.it]

Hi Patrick,

I'm trying to add also the spatial objects to the view3D as you  
suggested, but the RequestAddObject() method seems to accept only  
spatial object representation pointer as parameter...
About the scene graph, I connected both the view3D and the optical  
tracker controller to an axes object acting as a world coordinate  
system, shouldn't this work?
Thanks for helping

Alberto






Citando Patrick Cheng <cheng at isis.georgetown.edu>:

> Hi Alberto,
>
> Your approach is quite novel. Normally people think about register EM
> and Optical trackers together first, now you are tracking the EM
> tracker using Optical tracker.
>
> 1. One quick question:
> Did you calibrate the EM FieldGenerator with the opticalTrackerTool(0)?
> opticalTrackerTool(0) --> FieldGeneratorBoxObject
>
> You need to have this transform set properly to get the accurate
> position of the EM sensor in the optical tracker space.
>
> 2. To answer your question about what should be added to View3D.
>    You need to add also the spatial objects into View3D so it can render it.
>    You also need to connect your View3D to the scene graph tree, so it
> knows where to render those objects. In this case, you should try:
>
> View3D --> opticalTracker --> opticalTrackerTool(0) -->
> FieldGeneratorBoxObject --> magneticTracker --> magneticTrackerTool -->
> EM_Sensor_CylinderObject
>
> Hope this helps,
>
> Patrick
>
>
> alberto.vaccarella at mail.polimi.it wrote:
>> Hi everyone,
>>
>> I'm trying to develop an application using both an optoelectronic   
>> and a magnetic tracking system, the setup is as follows:
>>
>> - the optoelectronic device tracks some tools and the EM field generator
>>
>> - the magnetic device tracks one sensor with respect to the   
>> coordinate system of its EM field generator
>>
>> I want all the tools and the EM sensor to be displayed in the same   
>> coordinate system (the optical device one); to do that I:
>>
>> - instantiated 2 tracker controllers
>> - built the scene graph as follows (after the tracking has started ):
>>
>> opticalTracker --> opticalTrackerTool(0) -->   
>> FieldGeneratorBoxObject --> magneticTracker --> magneticTrackerTool  
>>  --> EM_Sensor_CylinderObject
>>
>> where:
>> - opticalTrackerTool(0) is the rigid body associated to the EM   
>> field generator
>>
>> Is this approach correct? What should I add to the view3D? I added   
>> the representations of the two objects but it doesn't work, it   
>> doesn't display anything...
>> Once I solve this I guess I have to use:
>>
>>      EM_Sensor_CylinderObject->RequestComputeTransformTo(opticalTracker)
>>
>> I'm not sure I got how to use this method...should I call it once   
>> or each time I need the transform? How could I make the   
>> EM_Sensor_CylinderObject to be always displayed in the   
>> opticalTracker coordinate system?
>>
>> Thanks in advance for any help
>> Alberto
>>
>>
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