[vtkusers] Glitch in rendering when using vtkGPUVolumeRayCastMapper in 7.0.0

[Elvis Stansvik]

2016-05-26 15:03 GMT+02:00 Andras Lasso <lasso at queensu.ca>:

> Maybe you’ve forgot to set the camera clipping range.
>

Hm, I realize I wasn't clear: The problem occurs only with the GPU mapper,
not with the software based one. So I don't think it's a clipping range
problem (since then it would show up in the software mapper as well). I've
also tried changing my clipping range and the effect is the same.

It occurs no matter how zoomed in/zoomed out I am, and seems to more have
to do with the angle I'm viewing the volume from.

Elvis


>
>
> Andras
>
>
>
> *From: *Elvis Stansvik <elvis.stansvik at orexplore.com>
> *Sent: *May 26, 2016 08:29
> *To: *VTK Users <vtkusers at vtk.org>
> *Subject: *Re: [vtkusers] Glitch in rendering when using
> vtkGPUVolumeRayCastMapper in 7.0.0
>
>
> 2016-05-26 14:01 GMT+02:00 Elvis Stansvik <elvis.stansvik at orexplore.com>:
>
>> 2016-05-26 13:46 GMT+02:00 Elvis Stansvik <elvis.stansvik at orexplore.com>:
>>
>>> Hi all,
>>>
>>> When I view my volume from certain angles, there are glitches in the
>>> rendering when using vtkGPUVolumeRayCastMapper , see attached screenshots
>>> when the glitch is occurring and when it is not.
>>>
>>> Has anyone seen this behavior and know what the problem might be? This
>>> is on Intel HD 4400 graphics.
>>>
>>
>> If it's not quite clear, the glitch is at the bottom of the first
>> screenshot, where an are of the volume is not visible.
>>
>
> An observation: I had the following to enable parallell projection in my
> code:
>
>     self.camera.ParallelProjectionOn()
>
> If I remove this line, so that perspective projection is used instead, the
> glitches disappear.
>
> This is not a solution, since I need to use parallell projection, but
> maybe it's a clue to the problem?
>
> Elvis
>
>
>> From certain angles the volume disappears almost completely.
>>
>> Elvis
>>
>>
>>>
>>> I would love to be able to use the GPU volume mapper since it's so much
>>> faster than the software one.
>>>
>>> Thanks,
>>> Elvis
>>>
>>
>>
>
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