[vtk-developers] [Non-DoD Source] Re: merge request for vtkCamera.cxx eyeseparation and near far planes correction (UNCLASSIFIED)

[Hennessey, Joseph G CTR USARMY RDECOM ARL (US)]

CLASSIFICATION: UNCLASSIFIED

The modifications that I have made are designed to bring the server side
rendering in line with the client rendering in ParaView.
They correct an issue where the server side render used in immersive ParaView
Display does not match what is generated and
Displayed in the ParaView client RenderWindow. The OffAxis projection code is
used on the server side, but is not used to generate
Images for the client display. My goal with these changes is to bring them
closer, but it does not bring them to pixel by pixel perfection,
which is perhaps not even possible given that there are using different
routines to calculate what to display. I do not know why
constants were originally chosen for the near and far planes, for example, but
I do know that they do not work well on different scaled
data clipping the data out of visibility. My changes allow data across a large
range of scales to be visualized and closely approximate
what would be displayed in the ParaView client RenderWindow.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joseph G. Hennessey Ph.D., Lockheed Martin
Army Research Lab
DOD Supercomputing Resource Center

-----Original Message-----
From: David Cole [mailto:DLRdave at aol.com]
Sent: Thursday, March 17, 2016 4:44 PM
To: Aashish Chaudhary <aashish.chaudhary at kitware.com>
Cc: Hennessey, Joseph G CTR USARMY RDECOM ARL (US)
<joseph.g.hennessey2.ctr at mail.mil>; paraview-developers at paraview.org;
vtk-developers at vtk.org
Subject: [Non-DoD Source] Re: [vtk-developers] merge request for vtkCamera.cxx
eyeseparation and near far planes correction (UNCLASSIFIED)

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----

OffAxis projection in VTK is woefully underdocumented, and accepting this pull
request will only add to the mystery.

I would suggest documenting that the coordinates used to specify it are in
vtkCamera coordinates (not world), and clarifying with comments in the code
what some of the constants used are for. Also, EyeSeparation appears to be
specified in meters, although it's unclear how it relates to any of the VTK
coordinate systems or to the size of the actual display being used.


2 cents,
David C.


On Thu, Mar 17, 2016 at 4:17 PM, Aashish Chaudhary
<aashish.chaudhary at kitware.com> wrote:
> Hi Joe,
>
> Thank for you for the PR. Could you please describe the problem in bit
> more detail?
>
> Thanks,
>
>
> On Thu, Mar 17, 2016 at 4:04 PM, Hennessey, Joseph G CTR USARMY RDECOM
> ARL
> (US) <joseph.g.hennessey2.ctr at mail.mil> wrote:
>>
>> CLASSIFICATION: UNCLASSIFIED
>>
>> Hello,
>>
>> I have modified
>>
>> Rendering/Core/vtkCamera.cxx:: ComputeOffAxisProjectionFrustum
>>
>> To fix a problem with eyeseparation and near and far planes for use
>> with immersive paraview
>>
>> The merge request is called
>>
>> fix ComputeOffAxisProjectionFrustum eyeseparation and near and far planes.
>>
>>
>> Caution-https://gitlab.kitware.com/vtk/vtk/commit/4fe4fabb420bba77740
>> ec988d060c5c296
>> d36afb
>>
>> Commit 4fe4fabb420bba77740ec988d060c5c296d36afb
>>
>> Authored by Joseph G. Hennessey about an hour ago
>> 1 parent d52198e1
>>
>> Please add this to VTK and indirectly to ParaView
>>
>> Thanks,
>>
>> Joe
>>
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> Joseph G. Hennessey Ph.D., Lockheed Martin Army Research Lab DOD
>> Supercomputing Resource Center
>>
>>
>> CLASSIFICATION: UNCLASSIFIED
>>
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>
>
>
> --
> | Aashish Chaudhary
> | Technical Leader
> | Kitware Inc.
> | Caution-http://www.kitware.com/company/team/chaudhary.html
>
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CLASSIFICATION: UNCLASSIFIED
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