POV-Ray : Newsgroups : povray.binaries.images : Luna, Moon... desert satellite Server Time
27 Oct 2021 06:24:41 EDT (-0400)
  Luna, Moon... desert satellite (Message 11 to 20 of 47)  
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From: Samuel B 
Subject: Re: Luna, Moon... desert satellite
Date: 11 Sep 2021 16:50:00
Message: <web.613d15f7756c3d5acb705ca46e741498@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 11/09/2021 om 02:36 schreef Samuel B.:
> > "Samuel B." <stb### [at] hotmailcom> wrote:
> > (...) Maybe POV-Ray is mishandling the tiff file?
> >
> And if you save the tiff as tga or png (using IC which I prefer), what
> happens?

Well, if I save it as a png file it gets /fixed/, that's what happens! Thanks
Thomas :D

The attached is what the POV-Ray render looks like now.

What's IC, btw? Did you mean IV aka IrfanView? I use that for many things, but
in this case it didn't help the situation whatsoever. Maybe I'm using it wrong.
Instead I used GIMP and exported the image to a png file with some options
enabled.

TL;DR: use GIMP to convert NASA's tiff files to a 16-bit png file using the
16bpc GRAY pixel format :)

Sam

P.S. I still wonder if POV-Ray is mishandling 16-bit grayscale tiff files...


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Attachments:
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Preview of image 'moon-success.jpg'
moon-success.jpg


 

From: Samuel B 
Subject: Re: Luna, Moon... desert satellite
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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From: Samuel B 
Subject: Re: Luna, Moon... desert satellite
Date: 11 Sep 2021 17:20:00
Message: <web.613d1ce4756c3d5acb705ca46e741498@news.povray.org>
=?UTF-8?Q?J=c3=b6rg_=22Yadgar=22_Bleimann?= <yaz### [at] gmxde> wrote:
> Hi(gh)!



> On 10.09.21 01:40, Samuel B. wrote:
> > I should probably try the maps them out in other programs to see
> > if POV is at fault, although I doubt it is.
>
> Is there anywhere on the Web a tool to convert 16-bit PNGs to 16-bit
> (red/green) POV-Ray heightfields?

Hmm, not to my knowledge. But I have done this myself in GLSL, although I may
have gotten my math slightly wrong. It can also be done in POV-Ray using
functions and color_maps, but again the math has to be /just/ right or else you
get unintended contour lines and/or slight terraces.

> Or any other way to handle 16-bit png in POV-Ray, i. e. so that
> eval_pigment() actually reads in 65536 rather than 256 different gray
> values?

Yes, I think I can help you with. POV-Ray is the program you need. Just use a
red/green map to build a height_field like you normally would. Situate an
orthographic camera over the hf, and center the hf to fill the screen. Give the
hf a planar pigment with a reversed color_map (so that white=peaks) and an
ambient 1 finish. You may also need to specify the following command line
options: +fg and File_Gamma=1.0. This is the way I have converted red/green maps
to 16-bit pngs in the past.

> Now playing: Love Now Till Eternity (Asia)

Cool band! I think my favorite is 'Don't Cry'

Sam


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From: Samuel B 
Subject: Re: Luna, Moon... desert satellite
Date: 11 Sep 2021 17:25:00
Message: <web.613d1e26756c3d5acb705ca46e741498@news.povray.org>
"Mr" <nomail@nomail> wrote:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> > "Samuel B." <stb### [at] hotmailcom> wrote:
> > >
> > > I just tried it out in Blender, and it looked okay at /first/, but it's hard to
> > > tell since for some reason Blender inverts the bump map for half the moon. (...)
> >
> > Here's the Blender test. I don't see any obvious terracing (but for some reason
> > the normal gets flipped on the lower left portion). (...)
>
> Thanks a lot for reporting the issue, do you think you could share a
> (simplified?) blend file or if needed zip with dependencies for the bug ?

Hi Mr,

As it turns out there was no issue whatsoever, except that which existed within
myself ;D I was misusing Blender's node system by trying to plug an image
directly to the displacement port. There was an intermediary I was missing: the
Displacement node.

Attached is the corrected Blender render.

Sam


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Attachments:
Download 'blender-moon-test1m_13s.jpg' (235 KB)

Preview of image 'blender-moon-test1m_13s.jpg'
blender-moon-test1m_13s.jpg


 

From: Thomas de Groot
Subject: Re: Luna, Moon... desert satellite
Date: 12 Sep 2021 02:19:58
Message: <613d9c0e$1@news.povray.org>
Op 11/09/2021 om 22:47 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 11/09/2021 om 02:36 schreef Samuel B.:
>>> "Samuel B." <stb### [at] hotmailcom> wrote:
>>> (...) Maybe POV-Ray is mishandling the tiff file?
>>>
>> And if you save the tiff as tga or png (using IC which I prefer), what
>> happens?
> 
> Well, if I save it as a png file it gets /fixed/, that's what happens! Thanks
> Thomas :D
> 
Wow... It was just a thought. I had the dim memory that tiff might be 
problematic...

> The attached is what the POV-Ray render looks like now.
> 
Yes! That is much better indeed.

> What's IC, btw? Did you mean IV aka IrfanView? I use that for many things, but
> in this case it didn't help the situation whatsoever. Maybe I'm using it wrong.
> Instead I used GIMP and exported the image to a png file with some options
> enabled.
> 
That is Ive's small (but not little) application: 
https://www.lilysoft.org/IC/ic_index.htm

> TL;DR: use GIMP to convert NASA's tiff files to a 16-bit png file using the
> 16bpc GRAY pixel format :)
> 
> Sam
> 
> P.S. I still wonder if POV-Ray is mishandling 16-bit grayscale tiff files...
> 


-- 
Thomas


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From: Samuel B 
Subject: Re: Luna, Moon... desert satellite
Date: 12 Sep 2021 16:25:00
Message: <web.613e61a1756c3d5acb705ca46e741498@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> schreef Samuel B.:
> >
> > What's IC, btw? Did you mean IV aka IrfanView? I use that for many things, but
> > in this case it didn't help the situation whatsoever. Maybe I'm using it wrong.
> > Instead I used GIMP and exported the image to a png file with some options
> > enabled.
> >
> That is Ive's small (but not little) application:
> https://www.lilysoft.org/IC/ic_index.htm

Thank you, that looks like just the ticket since it supports higher bit depths.
(For some reason Firefox flagged the site as potentially malicious. But I
downloaded the file, scanned it with Defender and then VirusTotal, and it turned
up clean.)

Sam


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From: Samuel B 
Subject: Re: Luna, Moon... desert satellite
Date: 12 Sep 2021 19:20:00
Message: <web.613e89f0756c3d5acb705ca46e741498@news.povray.org>
"Samuel B." <stb### [at] hotmailcom> wrote:
> Just testing out some moon maps.

Final render in this series. Zoom in to see all the details.

This version uses the medium-resolution color map 'lroc_color_poles_4k.tif', and
the highest resolution displacement map available: 'ldem_64_uint'. As a tiff.
that sucker is over 500mb in size, but only about 350mb as a png. It takes
several seconds for POV-Ray to parse it, but that's not so bad. (I converted the
map from tiff to png using Ive's nifty image program called IC. Thank you Ive
for the program, and thank you Thomas for the recommendation :))

The scene still uses radiosity and a reflecting plane, but I added ground fog
this time around. The sun's position is not realistic.

Sam

P.S. If you look closely, you'll find some interesting things... You can see
what appears to be scratches in the moon's surface. Were these caused by
asteroids that hit the moon at a glancing angle? You'll also see what appears to
be drifts of dust forming sinuous ridges. Were the asteroid impacts powerful
enough to vaporize minerals and cause temporary gaseous wind? Were these ridges
perhaps formed in part by electrostatic forces? Or were they simply the result
of traveling dust that happened to settle just right? I'd be interested in your
thoughts!


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Attachments:
Download 'moonb1m_56s-plus-lb7b55m_42s.jpg' (345 KB)

Preview of image 'moonb1m_56s-plus-lb7b55m_42s.jpg'
moonb1m_56s-plus-lb7b55m_42s.jpg


 

From: Thomas de Groot
Subject: Re: Luna, Moon... desert satellite
Date: 13 Sep 2021 02:48:53
Message: <613ef455$1@news.povray.org>
Op 12/09/2021 om 22:22 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> schreef Samuel B.:
>>>
>>> What's IC, btw? Did you mean IV aka IrfanView? I use that for many things, but
>>> in this case it didn't help the situation whatsoever. Maybe I'm using it wrong.
>>> Instead I used GIMP and exported the image to a png file with some options
>>> enabled.
>>>
>> That is Ive's small (but not little) application:
>> https://www.lilysoft.org/IC/ic_index.htm
> 
> Thank you, that looks like just the ticket since it supports higher bit depths.
> (For some reason Firefox flagged the site as potentially malicious. But I
> downloaded the file, scanned it with Defender and then VirusTotal, and it turned
> up clean.)
> 

Firefox does not react to IC here (reports it is clean) but it is never 
wrong to scan web stuff. It is my standard procedure for everything 
coming from outside.

I think you will like IC.

-- 
Thomas


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From: Thomas de Groot
Subject: Re: Luna, Moon... desert satellite
Date: 13 Sep 2021 04:12:06
Message: <613f07d6$1@news.povray.org>
Op 13/09/2021 om 01:14 schreef Samuel B.:
> "Samuel B." <stb### [at] hotmailcom> wrote:
>> Just testing out some moon maps.
> 
> Final render in this series. Zoom in to see all the details.
> 
> This version uses the medium-resolution color map 'lroc_color_poles_4k.tif', and
> the highest resolution displacement map available: 'ldem_64_uint'. As a tiff.
> that sucker is over 500mb in size, but only about 350mb as a png. It takes
> several seconds for POV-Ray to parse it, but that's not so bad. (I converted the
> map from tiff to png using Ive's nifty image program called IC. Thank you Ive
> for the program, and thank you Thomas for the recommendation :))
> 
> The scene still uses radiosity and a reflecting plane, but I added ground fog
> this time around. The sun's position is not realistic.
> 

Nice image! The details are very clear.

> Sam
> 
> P.S. If you look closely, you'll find some interesting things... You can see
> what appears to be scratches in the moon's surface. Were these caused by
> asteroids that hit the moon at a glancing angle? You'll also see what appears to
> be drifts of dust forming sinuous ridges. Were the asteroid impacts powerful
> enough to vaporize minerals and cause temporary gaseous wind? Were these ridges
> perhaps formed in part by electrostatic forces? Or were they simply the result
> of traveling dust that happened to settle just right? I'd be interested in your
> thoughts!
> 

The short answer, for both features: Lunar Rills --> either collapsed or 
not, lava tunnels.

-- 
Thomas


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From: Kenneth
Subject: Re: Luna, Moon... desert satellite
Date: 13 Sep 2021 10:40:00
Message: <web.613f623e756c3d5a4cef624e6e066e29@news.povray.org>
"Samuel B." <stb### [at] hotmailcom> wrote:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> > Just testing out some moon maps.
>
> Final render in this series. Zoom in to see all the details.
>
Superb. With a jet and its contrail superimposed (just for scale) we would be
hard-pressed to discern a difference from a real late-afternoon photo, made with
a telescopic lens.

> P.S. If you look closely, you'll find some interesting things...

> > [Thomas]
> > The short answer, for both features: Lunar Rills --> either collapsed or
> > not, lava tunnels.

On the infallible internet, I've read that such features are caused by roving
herds of Moon Calves munching on moon dust-- with the resulting 'production' of
methane clouds. Stinky methane wind, a little-known secret of the Moon...


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