POV-Ray : Newsgroups : povray.binaries.images : Luna, Moon... desert satellite : Re: Luna, Moon... desert satellite Server Time
16 Sep 2021 15:21:31 EDT (-0400)
  Re: Luna, Moon... desert satellite  
From: Samuel B 
Date: 11 Sep 2021 17:05:00
Message: <web.613d18d9756c3d5acb705ca46e741498@news.povray.org>
"Kenneth" <kdw### [at] gmailcom> wrote:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> > Hi,
> >
> > Just testing out some moon maps. (...)
>
> Hi Sam, it's great to see you posting on the newsgroups again.

Hello Kenneth, it's good to see that you're also still around.

> That's a beautiful image-- especially with the added Earth glow, as Thomas
> mentioned.

Thanks. The best part is that is renders quickly. But parse times do go up when
using the highest resolution displacement map. That map is about half a gig in
size.

> So the 'unsigned 16-bit' file is the displacement map you used (with its
> apparent 8-bit precision, and some reversed normals!); thanks for the info.
>
> Have you tried placing a 2nd Sun light_source on the other side of the Moon, to
> see what happens with the normals in the normally 'shadowed' half?

Okay, so as it turns out, I was misusing the map in Blender, and that's why the
normals were being reversed. Blender was probably trying to calculate the normal
from three separate color channels because I plugged the image directly into the
displacement slot. The trick is to use a special node
(Add->Vector->Displacement) and use that instead.

> It's interesting that the website's description of the color map says it was
> made with a gamma of 2.8; do you have any idea why that would be so (rather
> than, say, 2.2)?

Ask NASA ;) I'm sure there's a logical reason, and it probably has to do with
outdated color space specifications. Maybe Clipka would know...

Sam


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