[vtkusers] Clipping and vtkGPUVolumeRayCastMapper

[Paul Scully]

Hi, Andi.

 

I’ve also come across this problem, and refer you to this:  http://vtk.1045678.n5.nabble.com/My-investigation-results-on-the-three-vtkOpenGLGPUVolumeRayCastMapper-bugs-Please-read-td2473032.html

 

The clip-plane problem is addressed in the first section.  I modified my VTK (5.8) source as per the fix, and found it to be good.  Whether these three fixes are correct, and if so when will be available in VTK releases proper, is another issue =)

 

PaulScully

 

 

From: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] On Behalf Of Andreas Bruening
Sent: 05 September 2011 17:20
To: vtkusers at vtk.org
Subject: [vtkusers] Clipping and vtkGPUVolumeRayCastMapper

 

Hi all,

 

there is a strange behaviour when I put some clipplanes into my volumerendering scene. In my program I perform GPU accelerated volumerendering of medical data using vtkGPUVolumeRaycastMapper. I want to add some clipplanes to see what is inside a volume. It is often that the clipplanes clip wrong. The behaviour is similar to the bug reported here: 

http://www.vtk.org/Bug/view.php?id=12377 <http://www.vtk.org/Bug/view.php?id=12377> 

The mathematics in my code is correct. Origin and normal vector are set correct. When I change the mapper to vtkFixedPointVolumeRaycastMapper everything works fine. And the wrong clipping occurs when I use vtkInteractorStyleTrackballCamera and also when don’t use vtkInteractorStyleTrackballCamera and calculate the cameraposition by my own. 

Also I figured out that the wrong clipping occurs only when the clipplane normal is not orthogonal and it occurs always when the origin is (0, 0, 0).

Is somebody already working on it or does anyone know a workaround? 

 

Thanks in advance

Andi


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