POV-Ray : Newsgroups : povray.binaries.images : more leather grain tests Server Time
6 Nov 2024 00:28:47 EST (-0500)
  more leather grain tests (Message 1 to 9 of 9)  
From: Jim Charter
Subject: more leather grain tests
Date: 11 Apr 2005 17:41:14
Message: <425aeefa@news.povray.org>
at camera angles 5, 10, 20, 40

normal is basically

	crackle
	scale .04
	poly_wave .045
	pigment_map {
         	[0 rgb 0]
         	[1 rgb .7]
	}

averaged with some dents.

finish is


         diffuse 1
         specular .75
         roughness .035
         ambient 0
         reflection { .075 .15
                 fresnel 1
                 metallic 0
         }

Comments and criticism welcome.


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img.1044.jpg

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From: scott
Subject: Re: more leather grain tests
Date: 11 Apr 2005 17:57:51
Message: <425af2df$1@news.povray.org>
> Comments and criticism welcome.

I really like the texture around the specular highlights, especially near 
the buckle, looks very photorealistic.  But the "lighter" bit at the bottom 
edges looks wrong, it's all one colour, is this just a reflection of the 
walls?  Too much reflection then IMO, or maybe the walls are too bright, or 
too plain?


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From: Dave Matthews
Subject: Re: more leather grain tests
Date: 11 Apr 2005 18:05:01
Message: <web.425af439a4452e598c7259570@news.povray.org>
Jim Charter <jrc### [at] msncom> wrote:
>
> Comments and criticism welcome.

Girl's gonna fall off her shoes and break an ankle.  (My younger daughter,
10 yrs old, wants a pair like that; in a rare show of solidarity, her
mother and I vetoed the idea.)

Anyway, to the topic -- fantastic, as always, and thanks for the code.
Texture makes the image, and it's the thing I have the most difficulty
with.  Have you published any texture tutorials?  If not, get with it! ;-)
Your shoe-modeling tutorial helped my Wings skills immensely.

Dave Matthews


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From: Jim Charter
Subject: Re: more leather grain tests
Date: 11 Apr 2005 19:09:46
Message: <425b03ba$1@news.povray.org>
Dave Matthews wrote:

> 
> Girl's gonna fall off her shoes and break an ankle.  (My younger daughter,
> 10 yrs old, wants a pair like that; in a rare show of solidarity, her
> mother and I vetoed the idea.)

"Goth" at 10 years, sounds like trouble. Tattoo? Sounds like my sister's 
two girls actually.  My own 12 year old daughter's a jock.  Girly stuff 
scares her.

> 
> Anyway, to the topic -- fantastic, as always, and thanks for the code.

This is a variation on the leather texture I put on the Wiki

> Texture makes the image, and it's the thing I have the most difficulty
> with.  Have you published any texture tutorials?  If not, get with it! ;-)

Something that may be needed but a difficult topic to approach in a 
general way.  With texture it is very difficult to move seemlessly 
between the general and the specific.  That is I believe one of the 
difficulties with the endeavor in the wiki to produce a catalog of 
textures.  They are so dependent on context.

> Your shoe-modeling tutorial helped my Wings skills immensely.

Thanks for saying so.  And that may provide an approach for doing 
something with textures.  Just step through an anecdotal example and the 
issues that get touched on, are illustrated, other issues are not.


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From: Jim Charter
Subject: Re: more leather grain tests
Date: 11 Apr 2005 20:01:02
Message: <425b0fbe@news.povray.org>
scott wrote:
>>Comments and criticism welcome.
> 
> 
> I really like the texture around the specular highlights, especially near 
> the buckle, looks very photorealistic.  But the "lighter" bit at the bottom 
> edges looks wrong, it's all one colour, is this just a reflection of the 
> walls?  Too much reflection then IMO, or maybe the walls are too bright, or 
> too plain?
> 
> 
I think it is the reflection of the "table" surface.  I really need to 
do more experimenting with reflection, I don't really understand how it 
works.  I often seems to me that if there is *any* reflection on a 
surface, it 1mmediately makes it look like a highly reflective surface. 
  Still I no doubt I could reduce the reflection here to some benefit.

I am also not sure why the texture gets washed out in the reflection. 
But both of these effects may be present in the world but not really 
noticed by us.  For instance it my be that objects are often more 
reflective than we perceive them to be.  And that reflection tends to 
wash out surface texture to an extent, even though I'd have thought the 
opposite.  I have experimented a bit with the blurred reflection devices 
too but without satisfactory results.  I guess what I haven't tried is 
High aa, but I really can't see how it would have any effect.

Attached is one of my reference pictures for the shoes.  You can see 
that the finger and the throw sheet ground are both reflected quite 
clearly in the leather.


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From: Shay
Subject: Re: more leather grain tests
Date: 12 Apr 2005 11:18:17
Message: <425be6b9$1@news.povray.org>
Jim Charter wrote:

Looks like pleather or some other fake polished leather. Real leather 
doesn't have the sharp lines (noise) at the edge of the specular due to 
its being covered with pores.

I took some reference shots, three with a highlight and three without. 
Might be useful to you.
http://www.simcoparts.com/pics/leather

  -Shay


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From: Severi Salminen
Subject: Re: more leather grain tests
Date: 12 Apr 2005 12:55:36
Message: <425bfd88$1@news.povray.org>
Try to render it again with very strong antialiasing, like "+a0.0 +r4" 
(or whatever the level switch is). It might make the blurred reflections 
actually look blurred...

Or if it won't make, add a very small micronormals to the texture. 
Basically bumps scaled very small. And then render using strong 
antialiasing.


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From: Jim Charter
Subject: Re: more leather grain tests
Date: 12 Apr 2005 13:51:24
Message: <425c0a9c@news.povray.org>
Shay wrote:
> Jim Charter wrote:
> 
> Looks like pleather or some other fake polished leather. Real leather 
> doesn't have the sharp lines (noise) at the edge of the specular due to 
> its being covered with pores.
> 
> I took some reference shots, three with a highlight and three without. 
> Might be useful to you.
> http://www.simcoparts.com/pics/leather
> 
>  -Shay

Thanks for those.  I see from your example that the pitting from the 
pores and the wrinkly pebbled look can exist simultaneously with each 
other. Or in fact the pitting itself can look like pebbling.  If I reach 
over and pick up my Mizuno "Power Close" fielder's mitt here, and 
examine it's "supersoft one-touch" leather under the magnifying glass, I 
can see exactly the deep pitting that your photos exhibit.  But if I 
look on the other side of a seam, the pitting is not visible and the 
look is more wrinkly-pebbled.  This is also true if I examine the 
leather of my Lug boots.  So I wonder if the leather might actually have 
two sides, or some other characteristic, which are effected differently 
by the tanning.

Either way, neither look as smooth as do the examples I posted so thanks 
for the wakeup call.  I can intensify the deepth of the pebbling with 
the poly_wave value.  I can introduce pits by tweaking the color map I 
suspect.

Attached are two details from the source photo I have.  One is at the 
native resolution, the other is resampled and magnified.


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From: Alain
Subject: Re: more leather grain tests
Date: 13 Apr 2005 20:24:13
Message: <425db82d@news.povray.org>
Shay nous apporta ses lumieres en ce 2005-04-12 11:18:
> Jim Charter wrote:
> 
> Looks like pleather or some other fake polished leather.
> 
>
>  -Shay
Or sn overly waxed leather, or some varnished leather. You may also have leather that
have been 
"laminated" between steel rolers to make it ultra smooth. I'm thinking of some Italian
shoes that 
have a mirror like finish.

Alain


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