[IGSTK-Users] Problem with Image Representation: need help.

[vespasiano at libero.it]

Hello, I’m a new and inexpert user of IGSTK and I need to write an Augmented 
Reality application that is in part similar to the “Needle Biopsy” example that 
comes with IGSTK. To do so I use IGSTK 4.2 built with

-	ITK 3.8.0
-	FLTK 1.1.10
-	VTK 5.4.2
-	OpenCV 2.1.

I have edited a New Project in MS VS 2008 and I use the Needle Biopsy’s 
QuadrantViews as interface for slice and model visualization. I’ve copied the 
dicom load function and ConnectImageRepresentation from the example. Till now 
seems that all function correctly. I can load dicom, modify the slice number, 
pan, zoom and rotate the 3D view. In the 3D View, like the example, I have the 
dicom slice in the Image Representation.

Today I’ve tried to add entry, target, fiducial points and the path (object 
and representation) in the 3D View. The difference between the Example and my 
program is that that these object are translated in space because my dicom have 
a fixed offset of (15,-48,1497.5) respect the origin that is the world 
reference. So I need to connect the 3D model (ellipsoid and Tube) to the world 
reference not with an identity transform but with this translation transform.

The problem is here. The 3D model are initially correctly visualized in the 3D 
View but when I begin to rotate the 3D View they random disappear together with 
the slice Image representation. For example if want to rotate the 3D view to 
see the slice and object from the top along the axial axis, slice and object 
suddenly disappear during the rotation. Sometimes disappear a slice along one 
axis, for example the sagittal, sometimes along two. If I continue to rotate 
this could be appear but in a random manner.

I noted that this problem doesn’t appear in the NeedleBiopsy Example bue where 
the 3D object are centered to the WorldReference. 

I’m sorry for my orrible English. I need help and idea to resolve the problem. 
Many thanks. Francesco.