POV-Ray : Newsgroups : povray.binaries.images : An isosurface cloud. : Re: An isosurface cloud. Server Time
10 Dec 2023 13:07:09 EST (-0500)
  Re: An isosurface cloud.  
From: William F Pokorny
Date: 19 Aug 2020 08:20:19
Message: <5f3d1903$1@news.povray.org>
On 8/18/20 6:21 AM, BayashiPascal wrote:
> After Thomas' splines in isosurfaces, they are quite popular nowadays ! ;-)
Yes, with povr been trying to remove some of the longstanding code 
issues and functional limitations. We'll see.

> Your cloud looks more like smoke to me but the idea is very interesting. Thanks
> for sharing.

Yes, think you are right. The core issue is similar to what Kima has 
been asking about with color depth and banding. With isosurfaces, even 
forcing a lot of rays to be shot, you always have discrete shapes / 
grains at locations, unlike a media density of some kind. The isosurface 
jitter feature of povr helps a little with this, but it currently 
jitters only 'within' the accuracy amount.

If I apply some gaussian blurring with POV-Ray or external tool, I get 
something looking more cloud like, but not quite right on the fuzzy 
side. I could too probably help the cloud look by using some overall 
haze, but for this I wanted to better see the cloud structure. To 
explore / push the technique some.

I'll attach another variant where I cranked down on the gradient and 
accuracy while adding a second much smaller violent turbulence. To my 
eye less cloud like still, but interesting too. Not really sure what it 
looks like... Fuzzy fabric?

Aside: I reworked the fog feature in povr. Everything with it is depth 
based, but I have this rough idea forming in my head we might be able to 
do something interesting combining fog with isosurfaces of the fuzzy 
kind - maybe where some are all of the fuzzy shapes are transparent. 
Anyway, an idea for another day.

Bill P.

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