[vtk-developers] UseJitteringOn() has no effect in 7.1.0.rc1

[Elvis Stansvik]

2016-10-20 5:46 GMT+02:00 Alvaro Sanchez <alvaro.sanchez at kitware.com>:
> I ran your test program and I could reproduce the wood-grain artifacts you
> see.  It seems to me that the jitter noise might need some tweaking.  I will
> try a few things and investigate further, will let you know my findings.

Thanks Alvaro.

Elvis

>
>
> On Wed, Oct 19, 2016 at 8:07 AM, Elvis Stansvik
> <elvis.stansvik at orexplore.com> wrote:
>>
>> 2016-10-19 14:03 GMT+02:00 Alvaro Sanchez <alvaro.sanchez at kitware.com>:
>> > Hi Elvis,
>> >
>> > thanks for the test case.  Sorry, I did not have time to run it yet but
>> > I
>> > will have a look at it today.
>> >
>> > It seems unlikely to me that the small data spacing is affecting
>> > jittering.
>> > I will come back to you after debugging a bit with your test case.
>>
>> Alright, no hurry. Thanks a lot for having a look.
>>
>> Elvis
>>
>> >
>> > Cheers,
>> > Alvaro
>> >
>> > On Wed, Oct 19, 2016 at 1:54 AM, Elvis Stansvik
>> > <elvis.stansvik at orexplore.com> wrote:
>> >>
>> >> 2016-10-15 11:16 GMT+02:00 Elvis Stansvik
>> >> <elvis.stansvik at orexplore.com>:
>> >> > 2016-10-14 15:54 GMT+02:00 Alvaro Sanchez
>> >> > <alvaro.sanchez at kitware.com>:
>> >> >> Hi Elvis,
>> >> >>
>> >> >> the mapper uses a vtkPerlinNoise instance to generate the jitter
>> >> >> noise
>> >> >> and
>> >> >> as far as I know there are currently no knobs exposed to tweak the
>> >> >> amount of
>> >> >> ray perturbation.  Are you using the GL2 backend?  It would also be
>> >> >> good to
>> >> >> know what features are active along with ray jittering (multiple
>> >> >> components,
>> >> >> etc.), so if you could provide some sample data or code would be
>> >> >> very
>> >> >> helpful.
>> >> >
>> >> > Hi again Alvaro,
>> >> >
>> >> > Here's a minimal test case including sample data (129 MB):
>> >> >
>> >> >     https://dl.dropboxusercontent.com/u/22350696/test_grain.tar.gz
>> >> >
>> >> > Build with:
>> >> >
>> >> >     cmake .
>> >> >     make
>> >> >
>> >> > and run with:
>> >> >
>> >> >     ./test_grain rec-0300mm-0400mm.xml
>> >> >
>> >> > The result should be as in the attached screenshot.
>> >>
>> >> Anyone had time to run my test case? Are you seeing the same thing?
>> >>
>> >> Elvis
>> >>
>> >> >
>> >> > Elvis
>> >> >
>> >> >>
>> >> >> Thanks!
>> >> >> Alvaro
>> >> >>
>> >> >> On Fri, Oct 14, 2016 at 3:47 AM, Elvis Stansvik
>> >> >> <elvis.stansvik at orexplore.com> wrote:
>> >> >>>
>> >> >>> Hi all,
>> >> >>>
>> >> >>> I updated our product to use VTK 7.1.0.rc1, as I was interested in
>> >> >>> trying out vtkGPUVolumeRayCastMapper::UseJitteringOn() to get rid
>> >> >>> of
>> >> >>> some woodgrain effects we're suffering from in our volume rendering
>> >> >>> (mostly when the volumes are rendered very opaque).
>> >> >>>
>> >> >>> But turning the option on seems to have little to no effect. This
>> >> >>> is
>> >> >>> the result with the option on:
>> >> >>>
>> >> >>>     https://dl.dropboxusercontent.com/u/22350696/out.ogv
>> >> >>>
>> >> >>> It looks about the same to me as it does with the option off.
>> >> >>>
>> >> >>> Are there any knobs for this option? How does it determine how much
>> >> >>> to
>> >> >>> perturbate the rays?
>> >> >>>
>> >> >>> Thanks for any advise.
>> >> >>>
>> >> >>> Elvis
>> >> >>> _______________________________________________
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>> >> >>
>> >> >>
>> >> >>
>> >> >> --
>> >> >> Alvaro Sanchez
>> >> >> Kitware, Inc.
>> >> >> Senior R&D Engineer
>> >> >> 21 Corporate Drive
>> >> >> Clifton Park, NY 12065-8662
>> >> >> Phone: 518-881-4901
>> >
>> >
>> >
>> >
>> > --
>> > Alvaro Sanchez
>> > Kitware, Inc.
>> > Senior R&D Engineer
>> > 21 Corporate Drive
>> > Clifton Park, NY 12065-8662
>> > Phone: 518-881-4901
>
>
>
>
> --
> Alvaro Sanchez
> Kitware, Inc.
> Senior R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4901