[vtk-developers] Volume visualization with OpenVR

[Carlos Lopez]

Hi Aashish,

vtk is 7.1.1 with SHA:
b86da7eef93f75c4a7f524b3644523ae6b651bc4

the exact dataset I'm using is custom, but the issue might be the same with
any volumetric imagedata.

best,
carlos



On Mon, May 15, 2017 at 2:48 PM, Aashish Chaudhary <
aashish.chaudhary at kitware.com> wrote:

> Thanks for the images Carlos. Could you please send us the exact
> SHA/Version of VTK and also if you can point to the dataset (I know where
> it is but just in case).
>
> We have fixed a related view-clipping issue and since then we have not
> find any issues. It is possible that 1) There is a bug 2) This is related
> to perception since one eye is inside and the other is outside.
>
> - Aashish
>
> On Mon, May 15, 2017 at 12:52 PM Carlos Lopez <rcourant at gmail.com> wrote:
>
>> Hi Aashish,
>>
>> Here are the screenshots.
>>
>> In external.png, notice how the arm is being rendered differently for
>> this particular angle; in the HMD I get the sense there is a sharp edge
>> along the arm.
>>
>> When the camera is close enough, the mode of projection changes, and it
>> looks like internal.png; here I do not see any edges and the 3D effect
>> feels better to me.
>>
>> In the transition, for very specific points of view, I get the
>> in-between.png picture.
>>
>> I think the code is working as it should, but maybe a quick solution
>> would be to convince vtk that the data bounds are much larger that what
>> they really are so that it always renders as internal. Is there a way to do
>> this?
>>
>> thanks,
>> carlos
>>
>>
>>
>> On Mon, May 15, 2017 at 12:18 PM, Aashish Chaudhary
>> aashish.chaudhary at kitware.com> wrote:
>>
>>> Hi Carlos,
>>>
>>> Can you send a picture of the effect you are mentioning? We have a demo
>>> that uses VR in OpenVR but we didn't notice the artifact that you have
>>> mentioned but we also have not spent as much time as you did.
>>>
>>> - Aashish
>>>
>>> On Mon, May 15, 2017 at 11:42 AM Carlos Lopez <rcourant at gmail.com>
>>> wrote:
>>>
>>>> Hello,
>>>>
>>>> I'm visualizing a dataset from the visible human project using openVR
>>>> and I notice that when the camera is outside of the bounds of the dataset,
>>>> the data renders in a way that the bounding box is noticeable; because of
>>>> the stereo projection, It is possible to see that the volumetric data is
>>>> projected onto the faces of the bounding box (this is not visible in 2D,
>>>> either from a monitor or if I close one eye in the HMD).
>>>>
>>>> If the camera is inside the bounding box, then the data renders in a
>>>> way that this effect is no longer visible, the projection plane parallel to
>>>> the current view removes the small discontinuity and the 3D perspective is
>>>> restored.
>>>>
>>>> Is it possible to configure the volume rendering so that it always
>>>> behaves as if the camera is inside the dataset?
>>>>
>>>> thanks,
>>>> carlos
>>>>
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