search

visit-dav / visit

VisIt - Visualization and Data Analysis for Mesh-based Scientific Data
https://visit.llnl.gov
BSD 3-Clause "New" or "Revised" License
441 stars 116 forks source link

Spatial Anti-Aliasing in VisIt #18755

Open JustinPrivitera opened 1 year ago

JustinPrivitera commented 1 year ago

Take a look at this jet: jet with color

Let's look closer: jet aliasing

I have blown this up with MS paint and it has applied some smoothing that takes away from my point, but I think the image is still clear enough.

Notice the jagged lines on the wing and fins that should be smooth.

  1. Do we have any spatial anti-aliasing solution currently in visit? I couldn't find one from looking through the docs.
  2. If not, is it a good use of our time to add such a feature? It could be toggled on and off at will. Depends how important clean image quality is to us.
markcmiller86 commented 1 year ago

There is an antialiasing check-box ar the top of the rendering controls window. That said, I don't think we talk about it anywhere in the docs and I don't think it produces the greatest results either.

JustinPrivitera commented 1 year ago

I found it (why does it require a restart?). I honestly can't tell if it has made any difference for the image quality. If it has changed the image quality at all, it doesn't seem to have done much to get rid of the jagged edges on what should be straight lines.

Is it a spatial solution? Or some other kind of AA?

brugger1 commented 1 year ago

VTK has a software based antialiasing FXAA that they use in ParaView. It is done after the scene is rendered. Normal AA doesn't work with parallel rendering and that's why they use FXAA in ParaView. We can probably do the same. It's a single VTK call to turn it on. I'm not sure if it has options that control it.

Here is a link to more information about it.

https://www.kitware.com/new-fxaa-anti-aliasing-option-in-paraviewvtk/

markcmiller86 commented 1 year ago

FYI...

Filtering-Approaches-for-Real-Time-Anti-Aliasing.pdf