[Paraview-developers] [EXTERNAL] Re: Remind me - AA

[Scott, W Alan]

OK, much better pushback.  I would say AA (either the hack mentioned below or real) probably isn’t worth a non-trivial software change at this point.  We should keep it on the table for future work.

Alan

From: Moreland, Kenneth
Sent: Friday, July 01, 2016 7:58 PM
To: Scott, W Alan <wascott at sandia.gov>; David E DeMarle <dave.demarle at kitware.com>
Cc: paraview-developers at paraview.org
Subject: Re: [Paraview-developers] [EXTERNAL] Re: Remind me - AA

OK, let me rephrase my pushback. There are several technical hurtles to implement this feature. We know how to achive this effect, but it requires a non-trivial change to the rendering system that will take significant development cycles, add complexity to the rendering system, and potentially destabilize several features relying on the rendering. Plus, this is all happening in the middle of a push for other (more important) rendering features (OpenGL2, OpenSWR, Ospray, IndeX).

We turned off antialiasing in ParaView years ago because it caused way more problems than it was worth. The question is, do you really think it is important enough now to have a software push for it?

-Ken

From: Walter Scott <wascott at sandia.gov<mailto:wascott at sandia.gov>>
Date: Friday, July 1, 2016 at 12:12 PM
To: Kenneth Moreland <kmorel at sandia.gov<mailto:kmorel at sandia.gov>>, David E DeMarle <dave.demarle at kitware.com<mailto:dave.demarle at kitware.com>>
Cc: "paraview-developers at paraview.org<mailto:paraview-developers at paraview.org>" <paraview-developers at paraview.org<mailto:paraview-developers at paraview.org>>
Subject: RE: [Paraview-developers] [EXTERNAL] Re: Remind me - AA

Makes sense.  But…


1)      Make it 2X – i.e., 4 times the pixels, if the user asks for better images when lines are visible.  Default off.  You want better images, it will be slower (when lines are visible).

2)      We do it (when rendering off screen) all the time when making movies for the power wall.  I don’t see this as an issue…

3)      Have the line widths automatically written 2X requested width.  Thus, when it shrinks by 2, you get normal, poor man’s AA lines.

Alan

From: Moreland, Kenneth
Sent: Friday, July 01, 2016 9:20 AM
To: Scott, W Alan <wascott at sandia.gov<mailto:wascott at sandia.gov>>; David E DeMarle <dave.demarle at kitware.com<mailto:dave.demarle at kitware.com>>
Cc: paraview-developers at paraview.org<mailto:paraview-developers at paraview.org>
Subject: Re: [Paraview-developers] [EXTERNAL] Re: Remind me - AA

Reason 1: Increasing the resolution 2X increases the compositing overhead by up to 4. Increasing the resolution 4X increases the compositing time by up to 16. It can be a noticeable difference when rendering interactively.

Reason 2: There can be technical difficulties in rendering images that large. You are likely to have a rendering context of the original resolution. To render such large images with images/movies, it renders image tiles and stitches them together. This adds further overhead and complication in rendering.

Reason 3: Line width is measured in pixels. Changing the resolution of the image in this way will change the perceived line width.

-Ken

From: Paraview-developers <paraview-developers-bounces at paraview.org<mailto:paraview-developers-bounces at paraview.org>> on behalf of Walter Scott <wascott at sandia.gov<mailto:wascott at sandia.gov>>
Date: Thursday, June 30, 2016 at 7:48 PM
To: David E DeMarle <dave.demarle at kitware.com<mailto:dave.demarle at kitware.com>>
Cc: "paraview-developers at paraview.org<mailto:paraview-developers at paraview.org>" <paraview-developers at paraview.org<mailto:paraview-developers at paraview.org>>
Subject: Re: [Paraview-developers] [EXTERNAL] Re: Remind me - AA

OK, why can’t we do that?  Have a mode that internally runs 2X or 4X resolution, does the compositing, and then shrinks back to what the user wants?  Only turn it on when 3d lines are in the image?



From: David E DeMarle [mailto:dave.demarle at kitware.com]
Sent: Thursday, June 30, 2016 7:46 PM
To: Scott, W Alan <wascott at sandia.gov<mailto:wascott at sandia.gov>>
Cc: paraview-developers at paraview.org<mailto:paraview-developers at paraview.org>
Subject: [EXTERNAL] Re: [Paraview-developers] Remind me - AA


Antialiasing confuses depth compositing.
Better to save out images/movies at 4x resolution and resample outside of paraview.

On Thursday, June 30, 2016, Scott, W Alan <wascott at sandia.gov<mailto:wascott at sandia.gov>> wrote:
Why can’t we turn anti alias lines on?  I am doing a feature edges, and it looks horrible.

Thanks,

Alan

--------------------------------------------------------
W. Alan Scott
ParaView Support Manager

SAIC
Sandia National Laboratories, MS 0822
Org 9326 - Building 880 A1-K
(505) 284-0932   FAX (505) 284-5619
---------------------------------------------------------



--
David E DeMarle
Kitware, Inc.
R&D Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4909
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