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

[Ken Martin]

Not exactly related to this, but I did find a bug in our OpenVR code that I
will be pushing to a topic soon. It also includes some other performance
tweaks. The bug can have a big impact on performance as it could cause the
VR display to wait for the screen display vsync. I'll be pushing the fix
for the 7.1.1 release as well.

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-
>> tp5741338p5741457.html
>> Sent from the VTK - Users mailing list archive at Nabble.com.
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Please keep messages on-topic and check the VTK FAQ at:
>> http://www.vtk.org/Wiki/VTK_FAQ
>>
>> Search the list archives at: http://markmail.org/search/?q=vtkusers
>>
>> Follow this link to subscribe/unsubscribe:
>> http://public.kitware.com/mailman/listinfo/vtkusers
>>
>
>
>
> --
> Alvaro Sanchez
> Kitware, Inc.
> Senior R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4901
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at http://www.kitware.com/
> opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Search the list archives at: http://markmail.org/search/?q=vtkusers
>
> Follow this link to subscribe/unsubscribe:
> http://public.kitware.com/mailman/listinfo/vtkusers
>
>


-- 
Ken Martin PhD
Chairman & CFO
Kitware Inc.
28 Corporate Drive
Clifton Park NY 12065
518 371 3971

This communication, including all attachments, contains confidential and
legally privileged information, and it is intended only for the use of the
addressee.  Access to this email by anyone else is unauthorized. If you are
not the intended recipient, any disclosure, copying, distribution or any
action taken in reliance on it is prohibited and may be unlawful. If you
received this communication in error please notify us immediately and
destroy the original message.  Thank you.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtkusers/attachments/20161208/66674a81/attachment.html>