[vtkusers] Distortions in Volumerendering in VR-Mode (HTC Vive)

[Alvaro Sanchez]

I merged a branch that should fix some of the clipping/flickering issues
with volume rendering.

https://gitlab.kitware.com/vtk/vtk/merge_requests/2394


On Tue, Jan 10, 2017 at 1:31 PM, Ken Martin <ken.martin at kitware.com> wrote:

> I'm working on a Volume Rendering VR example right now so I'll see if I
> bump into the same issue.
>
> On Thu, Dec 8, 2016 at 8:40 AM, Sebastian Heerwald <bastiheerwald at live.de>
> wrote:
>
>> Hey,
>>
>>
>> Thank you for your reply.
>>
>> I have build a little program which only loads a volume dataset and
>> displays it within the RenderWindow.
>>
>> Since the OpenVR interface is a little bit hackish within VTK the only
>> thing that decides whether it renders for OpenVR or for normal 2D-Display
>> is whether we link against vtkOpenVR and vtkRenderingOpenVR modules or not.
>>
>> Everything code related is the same.
>>
>>
>> So to reply to your Question:
>>
>> > Could you try rendering a volume with an identity matrix set as its
>> transformation?
>>
>>
>> I've build this simple program and it only places a volume dataset within
>> the world without any transformation. The volume is directly given to the GPUVolumeRCMapper
>> without any transformation. In "2D"-Renderwindow everything is fine.
>> Also in anaglyph rendering I get a nice 3D View.
>>
>> But when I link against OpenVR module the view dependend distortions
>> appear within VR. I've tried some things.
>>
>> All I can say is, that the errors appear if I look at any edge or corner
>> of the surrounding (invisible) boundingbox around the rendered volume. If I
>> look directly on one side of the boundingbox everything seems fine.
>>
>>
>> The only thing I can imagine from this perspective is, that the GPUVolumeRCMapper
>> gets wrong view directions for the eyes. But the vtkOpenVRCamera objects
>> seems to do everything right.
>>
>>
>> I don't know how to adjust the clipping box / bounding box you mentioned.
>> Can you explain how I can do this, maybe this helps me to debug further?
>>
>>
>> Sincerely,
>>
>> Sebastian
>>
>> ------------------------------
>> *Von:* vtkusers <vtkusers-bounces at vtk.org> im Auftrag von Alvaro Sanchez
>> <alvaro.sanchez at kitware.com>
>> *Gesendet:* Mittwoch, 7. Dezember 2016 18:14
>> *An:* polybos
>> *Cc:* VTK Users
>> *Betreff:* Re: [vtkusers] Distortions in Volumerendering in VR-Mode (HTC
>> Vive)
>>
>> Hi,
>>
>> I have never tested the GPUVolumeRCMapper with OpenVR but as far as I
>> remember Ken mentioned some time ago that he encountered a clipping/bbox
>> related issue when adjusting the volume's orientation and position. Could
>> you try rendering a volume with an identity matrix set as its
>> transformation?,  this might give you a hint of what the mapper is doing
>> wrong.
>>
>> Cheers,
>> Alvaro
>>
>> On Wed, Dec 7, 2016 at 11:38 AM, polybos <franz at znarfsoft.de> wrote:
>>
>>> Sebastian Heerwald wrote
>>> > If I look onto the volume rendering and move around it, there appear
>>> > "refraction" lines.
>>>
>>> Unfortunately I cannot help with this issue but I would also be very
>>> pleased
>>> if someone could help here. Or did you, Sebastian, already achieve some
>>> more
>>> insights into this problem?
>>> I also get such distortions on the HTC Vive when using
>>> vtkVolumeRayCastMapper, while everything seems perfectly well in a
>>> mesh-only
>>> rendering.
>>>
>>> Does anyone have similar issues? Maybe with Occulus Rift? As far as I
>>> understand Sebastian just test with a HTC Vive. At least I can only test
>>> with a HTC Vive.
>>>
>>>
>>>
>>> --
>>> View this message in context: http://vtk.1045678.n5.nabble.c
>>> om/Distortions-in-Volumerendering-in-VR-Mode-HTC-Vive-tp5741
>>> 338p5741457.html
>>> Sent from the VTK - Users mailing list archive at Nabble.com.
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>>
>>
>>
>> --
>> Alvaro Sanchez
>> Kitware, Inc.
>> Senior R&D Engineer
>> 21 Corporate Drive
>> Clifton Park, NY 12065-8662
>> Phone: 518-881-4901 <(518)%20881-4901>
>>
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
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>>
>
>
> --
> Ken Martin PhD
> Chairman & CFO
> Kitware Inc.
> 28 Corporate Drive
> Clifton Park NY 12065
> 518 371 3971 <(518)%20371-3971>
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-- 
Alvaro Sanchez
Kitware, Inc.
Senior R&D Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4901
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