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From: David Given
Subject: Lunar terrain
Date: 9 Dec 2013 08:37:25
Message: <52a5c795@news.povray.org>
This is an anonymous little island in the Sea of Smyth, on the eastern
limb of the Moon (lat -7.80 lon 86.34). As you can see, the terraforming
program is well underway.

This was made using 6GB of lunar topography data from the Lunar
Reconnaissance Orbiter spacecraft, plus a bespoke tool of my own to
generate a mesh from it. It also adds a certain amount of procedural
deformation. This isn't particularly successful; I'm trying to make
steep slopes more interesting, but the rocky foreshore looks terrible.
My textures suck, too. Any suggestions for where to find better ones? I
need various kinds of vegetation and rock from a distance.

The trees are the standard maple from Povtree; they're 30 to 60m high,
which is kinda big but then this is the moon.

Render time was about one minute forty for the generation and parsing
and about seven minutes for the raytrace. The generated files are huge:
200m tokens, and take an age to parse.

-- 
┌─── dg@cowlark.com ─────
http://www.cowlark.com ─────
│ "There does not now, nor will there ever, exist a programming
│ language in which it is the least bit hard to write bad programs." ---
│ Flon's Axiom


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From: clipka
Subject: Re: Lunar terrain
Date: 9 Dec 2013 10:01:25
Message: <52a5db45$1@news.povray.org>
Am 09.12.2013 14:37, schrieb David Given:

> Render time was about one minute forty for the generation and parsing
> and about seven minutes for the raytrace. The generated files are huge:
> 200m tokens, and take an age to parse.

1m 40s for parsing = an age?

Man, you ain't seen nothin' yet :-P


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From: Thomas de Groot
Subject: Re: Lunar terrain
Date: 9 Dec 2013 10:08:24
Message: <52a5dce8@news.povray.org>
On 9-12-2013 14:37, David Given wrote:
> This was made using 6GB of lunar topography data from the Lunar
> Reconnaissance Orbiter spacecraft, plus a bespoke tool of my own to
> generate a mesh from it. It also adds a certain amount of procedural
> deformation. This isn't particularly successful; I'm trying to make
> steep slopes more interesting, but the rocky foreshore looks terrible.
> My textures suck, too. Any suggestions for where to find better ones? I
> need various kinds of vegetation and rock from a distance.
>

Nice landscape already. For textures I would strongly suggest to 
experiment with Jaime's from his Project Tierra: 
http://www.ignorancia.org/en/index.php?page=Project_Tierra

Those are some of the best I know about and form the basis of many of my 
landscape scenes.

Thomas


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From: Stephen
Subject: Re: Lunar terrain
Date: 9 Dec 2013 10:26:13
Message: <52a5e115$1@news.povray.org>
On 09/12/2013 1:37 PM, David Given wrote:
> Any suggestions for where to find better ones? I
> need various kinds of vegetation and rock from a distance.

No bad, China. '-)

For Grass I often use Rune S. Johansen's GRASS TEX include file.
I was going to post the link but when I try to go to it, Access Denied.

There is a link to the code here:
http://code.google.com/p/terraform/source/browse/trunk/terraform/data/include/grasstex.inc?r=8

But no examples. I have my original download if you want it.

-- 
Regards
     Stephen


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From: David Given
Subject: Re: Lunar terrain
Date: 9 Dec 2013 13:52:51
Message: <52a61183$1@news.povray.org>
On 09/12/13 15:26, Stephen wrote:
[...]
> For Grass I often use Rune S. Johansen's GRASS TEX include file.
> I was going to post the link but when I try to go to it, Access Denied.

Ooh, nice. It fakes grass using a single pigment rather than using lots
of primitives, so it's cheap for big areas. I'll have a go --- any ideas
how it looks at a distance? I doubt I'll get the camera closer than a
few hundred metres to the ground. And there's lots of other useful stuff
there I can steal^H^H^H^H^H research...

-- 
┌─── dg@cowlark.com ─────
http://www.cowlark.com ─────
│ "There does not now, nor will there ever, exist a programming
│ language in which it is the least bit hard to write bad programs." ---
│ Flon's Axiom


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From: David Given
Subject: Re: Lunar terrain
Date: 9 Dec 2013 19:41:08
Message: <52a66324$1@news.povray.org>
Update (just managed to catch the dawn light on the trees!), with some
vastly improved textures (not that you can see them because it's so
dark). There are three problems:

(a) nasty aliasing in the waves at the bottom --- I suspect this only
shows up because it's a 400x300 test render, but is there a good way to
make this look less bad in general?

(b) the Earth's gone brown --- this *might* be a real effect; I think
the sky is sucking the blue out of it;

(c) unpleasant banding in the sky.

The sky is a relatively straightforward Rayleigh media stolen from the
Terrapov project; code follows. Any suggestions on how to fix the
banding? I'm *this* close to doing a final render for someone...

#local Bottom_Of_Atmosphere = Nominal_Terrain_Radius + Atmosphere_Base;
#local Top_Of_Atmosphere = Bottom_Of_Atmosphere
	+ Atmospheric_Depth;

#local Base_Rayleigh_Power = 6.7;
#local Rayleigh_Factor = 1 / Atmospheric_Scale;
#local Rayleigh_Scale = 0.5;
#local Rayleigh_Power = Base_Rayleigh_Power * Rayleigh_Factor;

#local Rayleigh_Density =
	density	{
            #local height_from_centre =
	        function(x, y, z) {
	            sqrt(x*x + y*y + z*z)
	        }
	
	    #local height_from_surface =
	        function(x, y, z) {
	            height_from_centre(x, y, z) - Bottom_Of_Atmosphere
	        }
	
	    #local gravity_factor =
	        function(x, y, z) {
	            (1/3) * Bottom_Of_Atmosphere / height_from_centre(x, y, z)
	        }
	
		function
		{
			Rayleigh_Scale * exp(-Rayleigh_Power * height_from_surface(x, y, z)
            )
            	}
	}

#local Rayleigh_Colour = rgb <0.2061, 0.3933, 1.0>;

#local Rayleigh_Media =
	media {
		method 3
		samples 31
		scattering {
			RAYLEIGH_SCATTERING
			color 2.3 * Rayleigh_Colour / Atmospheric_Scale
			extinction 1
		}
		density {
			Rayleigh_Density
		}
	}

#local Sky_Object =
	difference {
		sphere {
			<0, 0, 0>, Top_Of_Atmosphere
		}
		sphere {
			<0, 0, 0>, Bottom_Of_Atmosphere
		}
		
		pigment	{
			rgbt 1
		}

		hollow
		
		interior
		{
			media
			{
				Rayleigh_Media
			}
		}
	}

-- 
┌─── dg@cowlark.com ─────
http://www.cowlark.com ─────
│ "There does not now, nor will there ever, exist a programming
│ language in which it is the least bit hard to write bad programs." ---
│ Flon's Axiom


Post a reply to this message


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From: clipka
Subject: Re: Lunar terrain
Date: 9 Dec 2013 19:52:44
Message: <52a665dc$1@news.povray.org>
Am 10.12.2013 01:41, schrieb David Given:
> Update (just managed to catch the dawn light on the trees!), with some
> vastly improved textures (not that you can see them because it's so
> dark).

I really, really love the lighting in this scene!


> There are three problems:
>
> (a) nasty aliasing in the waves at the bottom --- I suspect this only
> shows up because it's a 400x300 test render, but is there a good way to
> make this look less bad in general?

UberPOV's anti-aliasing mode 3 does a very good job with such stuff.


> (b) the Earth's gone brown --- this *might* be a real effect; I think
> the sky is sucking the blue out of it;

That is to be expected indeed; same effect as the sun going orange near 
the horizon.


> (c) unpleasant banding in the sky.
>
> The sky is a relatively straightforward Rayleigh media stolen from the
> Terrapov project; code follows. Any suggestions on how to fix the
> banding? I'm *this* close to doing a final render for someone...

Use jitter on the media samples.

If this makes the sky look too noisy, go for UberPOV's anti-aliasing mode 3.


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From: Thomas de Groot
Subject: Re: Lunar terrain
Date: 10 Dec 2013 03:15:06
Message: <52a6cd8a@news.povray.org>
On 9-12-2013 19:52, David Given wrote:
> On 09/12/13 15:26, Stephen wrote:
> [...]
>> For Grass I often use Rune S. Johansen's GRASS TEX include file.
>> I was going to post the link but when I try to go to it, Access Denied.
>
> Ooh, nice. It fakes grass using a single pigment rather than using lots
> of primitives, so it's cheap for big areas. I'll have a go --- any ideas
> how it looks at a distance? I doubt I'll get the camera closer than a
> few hundred metres to the ground. And there's lots of other useful stuff
> there I can steal^H^H^H^H^H research...
>

It looks very good at a distance and even close up it is more than 
acceptable, so you should not have any problems there.

Thomas


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From: Stephen
Subject: Re: Lunar terrain
Date: 10 Dec 2013 03:40:00
Message: <web.52a6d342a77060737d8c6e9c0@news.povray.org>
David Given <dg### [at] cowlarkcom> wrote:
> On 09/12/13 15:26, Stephen wrote:
> [...]
> > For Grass I often use Rune S. Johansen's GRASS TEX include file.
> > I was going to post the link but when I try to go to it, Access Denied.
>
> Ooh, nice. It fakes grass using a single pigment rather than using lots
> of primitives, so it's cheap for big areas. I'll have a go --- any ideas
> how it looks at a distance? I doubt I'll get the camera closer than a
> few hundred metres to the ground. And there's lots of other useful stuff
> there I can steal^H^H^H^H^H research...
>

I have used a couple of times for TC-RTC competitions.
In neither of them did I pay much attention to the grass as my attention was on
other aspects if the image </excuses>

http://i.imgur.com/Fg92iNR.jpg

This one the path is defined in the macros, I think. Anyway it is almost a
direct steal from the example file.
BTW Please don't mock my Auntie Jessie. :-)

http://i.imgur.com/x3QpXKM.jpg

Stephen


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From: Thomas de Groot
Subject: Re: Lunar terrain
Date: 10 Dec 2013 07:20:09
Message: <52a706f9@news.povray.org>
On 10-12-2013 9:39, Stephen wrote:
> David Given <dg### [at] cowlarkcom> wrote:
>> On 09/12/13 15:26, Stephen wrote:
>> [...]
>>> For Grass I often use Rune S. Johansen's GRASS TEX include file.
>>> I was going to post the link but when I try to go to it, Access Denied.
>>
>> Ooh, nice. It fakes grass using a single pigment rather than using lots
>> of primitives, so it's cheap for big areas. I'll have a go --- any ideas
>> how it looks at a distance? I doubt I'll get the camera closer than a
>> few hundred metres to the ground. And there's lots of other useful stuff
>> there I can steal^H^H^H^H^H research...
>>

Also from the TC-RTC comes this image where I used Rune's grass macro, 
with the 'path' variation and the flowers: 
http://www.tc-rtc.co.uk/imagenewdisplay/stills/index418.html

This goes from near to far and view remains good. The 3D effect of the 
grass is mainly controlled by the distance between the ground 
height_field and the 'fake' grass, which is a copy of the height_field 
in fact. Note however, that I added some 'real' grass patches.

Thomas


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