[Paraview] Revisiting aliasing effect

[Den Fairol]

Hello Lis,

 

I suppose you are right on the step-size parameter thing since tweaking
NVIDIA's multi-sampling/anti-aliasing option on both Windows and Linux
systems does not seem to bring any change to the quality. On Linux,
performing Extract Subset at ROI sufficiently significant will result in a
superior image quality whereas on Windows, ROI has no effect over quality.
Of course, committing ROI implicates data loss, thus not a viable solution
either, especially when Windows has no such predicament. Furthermore, it
still does not explain why the different behavior/quality coming from the
same ParaView version (or different versions for that matter). It does
however, affect the Color Map Editor's color palette - noisy color
spectrum/gradient with the AA on NVIDIA control panel set to naught. If this
step-size property is the answer, where can I find it and how much work is
required? For the record, the problem is concerning still-image quality, not
the one during interaction (which is expected to be in low-resolution).

 

Regards,

Den

 

 

From: Lisa Avila [mailto:lisa.avila at kitware.com] 
Sent: 06 February 2014 10:01 PM
To: Den Fairol
Cc: paraview at paraview.org
Subject: Re: [Paraview] Revisiting aliasing effect

 

Hello Den,

This actually has nothing to do with NVIDIA antialiasing and probably
everything to do with the step size used on the mapper. Most likely the
issue is related to the automatic trade-off of quality to ensure performance
(depending on the mapper being used it will increase step size, decrease the
size of the generated image, and/or decrease the volume size in order to
meet the desired update rate). So either you are not seeing the "final"
image (which should fill in with better quality than the interactive image)
or for some reason the image is taking so long that the mapper thinks that's
the best it can do within its allocated time slice. Do you see a change in
image quality when you stop rotating? Are you having performance issue while
rotating?

Lisa

 

On Thu, Jan 30, 2014 at 2:45 AM, Den Fairol <den.fairol at infovalley.net.my>
wrote:

Hi, 

 

I'm a little confused regarding the inconsistent behavior of ParaView
(v4.x), specifically the quality of its volume rendering representation. The
Smart/GPU renderer for Windows version is slightly inferior to its RayCast
renderer counterpart whereas for the Unix/Linux version, it is kind of like
something you'd expect from a 'B' horror movie (see attachment for
Smart/GPU-based rendered images). It is mentioned here:
http://www.paraview.org/pipermail/paraview/2011-June/022062.html &
http://www.paraview.org/pipermail/paraview/2010-June/017961.html that
anti-aliasing (AA) is disabled by default. Then how could the Windows
(Windows 7, NVIDIA Quadro 600 + driver v320.xx) version persist to appear so
smooth despite setting NVIDIA's Control Panel AA handling to 'Off'?
Conversely, changing the same option in Linux (Ubuntu 12.04, NVIDIA Quadro
K5000 + driver v304.xx/v319.xx/v331.xx) to 'Override-application' adds
nothing to the quality. As of now, RayCasting is may not be a viable
solution since it induces substantial latency overhead.

 

Regards,

Den

 


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